,,cambridge ,,biological ,,series ,,fossil ,,plants ,,cambridge ,,university ,,press ,c4 ,f4 ,,clay1 ,manager ,london3 ,,fetter ,,lane1 ,e4,c4 ,edinburgh3 #ajj ,,princes ,,street ,illustration ,london3 ,h4 ,k4 ,,lewis ,,and ,,co4 ,ltd41 #acf1 ,,gower ,,street1 ,w4,c4 ,london3 ,,william ,,wesley ,,and ,,son1 #bh1 ,,essex ,,street1 ,,strand ,new ,york3 ,g4 ,p4 ,,putnam',s ,,sons ,bombay1 ,calcutta and ,madras3 ,,macmillan ,,and ,,co41 ,ltd4 ,toronto3 ,j4 ,m4 ,,dent ,,and ,,sons1 ,ltd4 ,tokyo3 ,,the ,,maruzen-,,kabushiki-,,kaisha ,all rights reserved ,illustration3 ,,charles ,,ren ,,zeiller ,membre de l',institut ,inspecteur gnral des ,mines ,professeur l'cole ,nat ,suprieure des ,mines 7#ahdg-aiae7 ,,fossil ,,plants ,a ,,text-,,book ,,for ,,students ,,of ,,botany ,,and ,,geology ,,by ,a4 ,c4 ,,seward ,m4,a41 ,f4,r4,s41 ,hon4 ,sc4,d4 ,dublin ,,professor ,,of ,,botany ,,in ,,the ,,university2 ,,master ,,of ,,downing ,,college ,,and ,,honorary ,,fellow ,,of ,,emmanuel ,,college1 ,,cambridge ,,with #bec ,,illustrations ,,volume ,,iii ,,pteridospermeae1 ,,cycadofilices1 ,,cordaitales1 ,,cycadophyta ,,cambridge3 ,,at ,,the ,,university ,,press #aiag ,,to ,,the ,,memory ,,of ,,my ,,friend ,,charles ,,ren ,,zeiller ,,illustrious ,,as ,a ,,man ,,of ,,science ,,and ,a ,,noble-,,hearted ,,gentleman ,,whom ,,to ,,know ,,was ,,to ,,revere ,,preface ,in the ,preface to ,volume ,,ii published in #aiaj ,i rashly stated that it was my intention 8to devote such space as is available within the limits of a text-book to the neglected subject of the geographical distribution of plants at different stages in the history of the earth10 also that ,volume ,,iii would be completed with as little delay as possible4 ,though nearly seven years have elapsed since the publication of the second volume it may fairly be said that the delay is not entirely due to causes which it was in my power to control4 ,the subject of geographical distribution receives no connected treatment in ,volumes ,,iii and ,,iv for the simple reason that ,i underestimated the space required for the description of the ,gymnosperms4 ,the alternatives were either to insert a greatly compressed survey of the successive floras of the world at the end of ,volume ,,iv or to attempt a fuller and less technical treatment of the subject in a separate book4 ,in choosing the latter course ,i am conscious that a further obligation is undertaken which it may not be possible to fulfil2 but the risk is deliberately taken4 ,volume ,,iv is in the press and will1 it is hoped1 be published before the end of #aiag4 ,it is a pleasant duty to repeat my thanks to many friends who have helped me in various ways4 ,dr ,kidston generously and without reserve allowed me access to his splendid collection of ,palaeozoic plants1 and the frequent occurrence of his name in the list of illustrations shows how freely ,i have availed myself of his kindness4 ,he has read some of the chapters and greatly assisted me by his friendly criticism and encouragement4 ,by reading the proofs of this volume ,dr ,scott has further increased my already large debt to him4 ,it is impossible to thank him adequately2 he not only corrected many careless mistakes but by wise counsel and advice he rendered me a service which ,i greatly appreciate4 ,the exchange of views with ,prof4 ,zeiller has been a constant source of profit and enjoyment1 and it is hard to realise that the completed book will not receive his kindly criticism4 ,he was a singularly unselfish and generous colleague1 always ready to help fellow workers1 and he had the faculty in an unusual degree of influencing those who had the privilege of his friendship by his sound advice and lovable personality4 ,the death of ,count ,solms-,laubach has deprived ,palaeobotany of one of its most learned and strongest supporters4 ,in common with all students of fossil plants ,i owe much to the critical treatment of the subject in the ,einleitung in die ,palophytologie4 ,prof4 ,jeffrey has very kindly given me several photographs and sections which have been of great service1 and ,i am similarly indebted to ,prof4 ,zalessky4 ,to ,prof4 ,nathorst my thanks are due for the great interest he has taken in my work and for his generosity in providing drawings and showing to me many of the treasures in the famous ,stockholm ,museum4 ,prof4 ,bertrand and ,prof4 ,lignier freely supplied photographs and drawings of specimens in their possession1 and ,i am particularly grateful to them for the willingness with which they always responded to my requests4 ,through the death of ,prof4 ,lignier in ,march #aiaf ,palaeobotany has been deprived of another original thinker who devoted himself with whole-hearted enthusiasm to botanical research and for many years faithfully served the ,university of ,caen3 he was a generous friend to whom one never appealed in vain for assistance4 ,through the kindness of the ,director of the ,indian ,geological ,survey ,i have been able to examine several fossils from the ,calcutta ,museum described by ,oldham and ,morris and by ,feistmantel4 ,with the ,director's permission several photographs and drawings made for a forthcoming paper to be published by the ,indian ,survey are reproduced in this volume4 ,i take this opportunity of thanking friends in ,australia who recently afforded me facilities for examining fossil plants in their charge1 and ,i would especially thank ,mr ,a4 ,b4 ,walkom of the ,university of ,brisbane1 who has recently undertaken an investigation of the rich plant-beds in the ,ipswich district1 for all that he did to enable me to make the most of a very short time available for palaeobotanical work4 ,for the loan of specimens and for other help ,i am indebted to ,prof4 ,bayly ,balfour1 ,prof4 ,bower1 ,prof4 ,margaret ,benson1 ,prof4 ,oliver1 ,sir ,david ,prain1 ,dr ,smith ,woodward1 ,prof4 ,weiss1 the ,director of the ,geological ,survey1 ,dr ,a4 ,h4 ,church1 ,dr ,arber1 and other friends4 ,i would also acknowledge a debt1 by no means inconsiderable1 to my ,colleague ,mr ,hamshaw ,thomas4 ,among younger friends in the ,cambridge ,botany ,school to whom ,i am indebted ,i wish particularly to thank ,miss ,ruth ,holden1 ,miss ,bancroft1 ,mr ,sayers1 ,mr ,dutt and others who have rendered me willing help4 ,in the ,list of ,illustrations mention is made of ,corporate ,bodies and individuals from whom blocks have been obtained1 and ,i am grateful to them for readily responding to my applications4 ,my ,wife1 though prevented by more urgent calls in the later stages of my task from giving as much time to the illustrations as in the two former volumes1 has contributed several drawings1 and my daughter ,phyllis ,seward has also given me much help in preparing drawings from previously published figures4 ,in spite of the vigilance and wise counsel of many friends numerous blemishes remain and for these the author is alone responsible4 ,a4 ,c4 ,,seward4 ,downing ,college ,lodge1 ,february #aj1 #aiag4 99 99 99 99 99 ,note4 ,the letters ,a and ,b added to references in the footnotes indicate that the works will be found in the ,bibliographies at the end of ,volumes ,i and ,,ii4 ,,table ,,of ,,contents ,,chapter ,,xxviii ,,cycadales 7,recent74 ,pp4 #a-cd4 ,,chapter ,,xxix ,,pteridospermeae 7continued from ,volume ,,ii74 ,pp4 #ce-he4 ,,page ,i4 ,,lyginopterideae #ce-he ,lyginopteris #ce-gj ,telangium #ed1 #ee2 ,lagenostoma #ee-fd2 ,lagenospermum #fd-ff2 ,pterispermostrobus #ff1 #fg4 ,heterangium #gj-he ,sphaerostoma #gh-ha4 ,,chapter ,,xxx ,,ii4 ,,medulloseae #hf-afe i4 ,medullosa #hf-aji1 #aef-afc ,myeloxylon #ajf-aaj2 ,neuropteris #aaj-aag2 ,alethopteris and ,linopteris #aac2 ,trigonocarpus #aag-abd2 ,codonotheca #abd-abf2 ,schtzia #abf-abh2 ,whittleseya #abh-aca2 ,dolerophyllum #acb-aci2 ,ottokaria #aci-ada2 ,strobilites #ada1 #adb4 ii4 ,colpoxylon #adb-ade iii4 ,rhexoxylon #adf-adi iv4 ,sutcliffia #adi-aef ,general considerations suggested by the anatomical features of ,medullosa #aef-afc ,,ii4 ,a4 ,,steloxyleae #afc-afe ,steloxylon #afc-afe ,,chapter ,,xxxi ,,pteridospermeae4 7,foliage and seeds47 ,pp4 #aff-agd4 ,pecopteris ,pluckeneti #aff-afh2 ,eremopteris artemisaefolia #afi-agb2 ,wardia #agb1 #agc2 ,adiantites bellidulus and ,lagenospermum ,arberi #agc1 #agd4 ,,chapter ,,xxxii ,,cycadofilices4 ,pp4 #age-bac4 ,i4 ,,megaloxyleae #age-ahj ,megaloxylon #age-ahj ,,ii4 ,,rhetinangieae #aha-ahc ,rhetinangium #aha-ahc ,,iii4 ,,stenomyeleae #ahc-ahe ,stenomyelon #ahc-ahe ,,iv4 ,,cycadoxyleae #ahe-aij ,cycadoxylon #ahe-ahg ,ptychoxylon #ahg-aij ,v4 ,,calamopityeae #aij-bjj ,calamopitys #aij-aif ,kalymma #aid-aif ,eristophyton #aig-bjj ,,vi4 ,,cladoxyleae #bjj-baj ,cladoxylon #bja-bjg ,vlkelia #bjh-baj ,,vii4 ,,protopityeae #baj-bac ,protopitys #baj-bac ,,chapter ,,xxxiii ,,cordaitales4 ,pp4 #bad-bii4 ,a4 ,,poroxyleae #bad-bai ,poroxylon #bad-bai ,b4 ,,cordaiteae #bai-bhd ,cordaites #bai-bfe ,noeggerathiopsis #bch-bdc2 ,rhiptozamites #bdd1 #bde2 ,phylladoderma #bdd2 ,euryphyllum #bde2 ,artisia #bdf-bdh2 ,dadoxylon #bdh-bfj2 ,metacordaites #bfj1 #bfa2 ,cordaianthus #bfd-bgj2 ,mesoxylon #bgj-bge2 ,pelourdea #bgg-bha2 ,niponophyllum #bhb1 #bhc2 ,titanophyllum #bhc1 #bhd4 ,,chapter ,,xxxiv ,c4 ,,pityeae #bhe-bii ,pitys #bhe-bhi ,archaeopitys #bij ,callixylon #bia-bic ,coenoxylon #bic1 #bid ,parapitys #bid1 #bie ,mesopitys #bie1 #bif ,antarcticoxylon #bif-bii ,,chapter ,,xxxv ,,palaeozoic ,,gymnospermous ,,seeds4 ,pp4 #cjj-cfe4 ,i4 ,lagenostomales #cjh-cah ,physostoma #cji-cab2 ,conostoma #cac-caf2 ,sphaerostoma #caf2 ,lagenostoma #caf2 ,gnetopsis #cag1 #cah4 ,,ii4 ,trigonocarpales #cah-ccb ,trigonocarpus #cai-cba2 ,tripterospermum #cba2 ,ptychotesta #cba2 ,hexapterospermum #cba-cbc2 ,polypterospermum #cbc2 ,pachytesta #cbc-cbf2 ,stephanospermum #cbf-cbi2 ,polylophospermum #cbi1 #ccj2 ,codonospermum #ccj1 #cca2 ,aetheotesta #cca1 #ccb2 ,eriotesta #ccb2 ,gaudrya #ccb4 ,,iii4 ,cardiocarpales #ccb-cef ,cardiocarpus #cch-cdj2 ,cyclospermum #cdj1 #cda2 ,cycadinocarpus #cda2 ,rhabdocarpus and ,rhabdospermum #cda-cde2 ,mitrospermum #cde1 #cdf2 ,diplotesta #cdf2 ,leptocaryon #cdf1 #cdg2 ,taxospermum #cdg2 ,compsotesta #cdg1 #cdh2 ,samaropsis #cdh-ced2 ,cordaicarpus #ced-cef4 ,,iv4 ,miscellaneous ,seeds #cef-cfe i4 ,hexagonocarpus #cef1ceg2 ,decagonocarpus #ceg2 ,polypterocarpus #ceg1 #ceh2 ,rhynchogonium #ceh-cfj2 ,boroviczia #cfj2 ,diplopterotesta #cfj1 #cfa2 ,musocarpus #cfa2 ,holcospermum #cfa-cfc4 ii4 ,malacotesta #cfc2 ,thysanotesta #cfd2 ,carpolithus #cfd1 #cfe2 ,microspermum #cfe4 ,,chapter ,,xxxvi ,,cycadophyta 7,fossil74 ,pp4 #cff-dbj4 ,,bennettitales #cfg-dbj ,cycadeoidea #cfg-dag ,cycadella #dag1 #dah ,amphibennettites #dah ,vectia #dai1 #dbj ,,chapter ,,xxxvii ,,bennettitales 7continued7 #dba-dgg ,williamsonia #dba-dfc ,wielandiella #dfc-dfg ,williamsoniella #dfg-dgc ,cycadocephalus #dgc-dge ,weltrichia #dge-dgg ,,chapter ,,xxxviii ,,cycadophyta4 ,pp4 #dgh-ejf4 i4 ,bucklandia #dhj-dij2 ,cycadeomyelon #dij1 #dia2 ,colymbetes #dia-did2 ,cycadeolepis #did-dif4 ii4 ,carpolithus #dig-ejj2 ,cycadospadix #ejj1 #eja2 ,beania #ejb2 ,zamiostrobus1 ,cycadeostrobus #ejc-eje2 ,androstrobus #eje1 #ejf4 ,,chapter ,,xxxix ,,cycadophyta 7,fronds74 ,pp4 #ejg-eia4 ,i4 ,bennettitales #eab-eff ,ptilophyllum #eab-ebi2 ,zamites #ebi-ecg2 ,otozamites #ecg-ede2 ,dictyozamites #edf-edh2 ,pterophyllum #edh-eeh2 ,cycadites and ,pseudocycas #eeh-eff4 ,,ii4 ,nilssoniales #eff-ehg ,nilssonia #eff-egh2 ,ctenis #egh-ehc2 ,pseudoctenis #ehd-ehg4 ,,iii4 ,incertae sedis #ehg-eia ,sphenozamites #ehg-ehi2 ,plagiozamites #ehi1 #eij2 ,cycadorachis #eij1 #eia4 ,list of ,works referred to in the ,text 7,vols4 ,,iii ,,iv74 #eib-fci ,index #fdj-fef ,,list ,,of ,,illustrations ,several of the illustrations are printed from blocks for which ,i am indebted to learned societies or to individuals4 ,the sources from which clichs were obtained are mentioned within square brackets4 ,the names of donors of photographs or drawings are added after the descriptions of the figures4 ,frontispiece4 ,charles ,ren ,zeiller4 ,from a photograph given to me by ,madame ,zeiller4 ,,fig4 ,,page #cgg4 ,cycas circinalis4 ,a4 ,malins ,smith #b #cgh4 ,cycas revoluta4 ,g4 ,r4 ,wieland4 #c #cgi4 ,encephalartos horridus #c #chj4 ,cycas circinalis4 ,encyclopaedia ,britannica4 #d #cha4 ,cycas revoluta and ,zamia ,loddigesii #e #chb4 ,encephalartos ,ghellinckii4 ,camb4 ,phil4 ,soc4 #aa #chc4 ,cycas siamensis4 ,encyclopaedia ,britannica4 #ab #chd4 ,cycas circinalis #ac #che4 ,cycas ,micholitzii and ,zamia angustifolia #ad #chf4 ,encephalartos ,altensteinii2 ,dioon edule4 ,s4 ,m4 ,wadham4 #ae #chg4 ,cycadean ,fronds #af #chh4 ,zamia ,wallisii #ag #chi4 ,zamia integrifolia4 ,camb4 ,univ4 ,press4 #ah #cij4 ,zamia ,loddigesii #ah #cia4 ,bowenia spectabilis4 ,encyclopaedia ,britannica4 #bj #cib4 ,cycas pectinata1 ,c4 ,riuminiana1 ,c4 angulata1 ,encephalartos1 and ,stangeria #ba #cic4 ,stangeria1 ,encephalartos1 and ,ceratozamia #bb #cid4 ,macrozamia ,preissii4 ,camb4 ,univ4 ,press4 #bc #cie4 ,zamia floridana4 ,g4 ,r4 ,wieland4 #bd #cif4 ,dioon edule1 ,cycas circinalis1 etc41 ,encephalartos1 ,bowenia1 ,macrozamia1 ,microcycas #bf #cig4 ,stangeria paradoxa4 ,new ,phytologist2 ,a4 ,g4 ,tansley4 #bi #cih4 ,macrozamia #bi #cii4 ,cycadean foliar bundles #ca #djj4 ,cycas ,micholitzii4 ,camb4 ,phil4 ,soc4 #cc #dja4 ,lyginodendron ,landsburgii4 ,r4 ,kidston #cg #djb4 ,lyginopteris oldhamia4 ,camb4 ,phil ,soc4 #ci #djc-dje4 ,lyginopteris oldhamia #da1 #dd1 #dh #djf4 ,lyginopteris oldhamia4 ,f4 ,w4 ,oliver #di #djg4 ,crossotheca ,hoeninghausi4 ,r4 ,kidston and other sources #ec #djh4 ,lagenospermum ,sinclairi2 ,lagenostoma2 ,calymmatotheca ,stangeri2 ,crossotheca ,hoeninghausi #eg #dji4 ,lagenostoma #eh #daj4 ,lyginopteris oldhamia #fi #daa1 #dab4 ,heterangium ,grievii #gc1 #gf #dac4 ,sphenopteris elegans #gh #dad4 ,sphaerostoma ovale #gi #dae4 ,heterangium ,grievii2 ,h4 tiliaeoides2 ,lyginopteris root #hb #daf4 ,medullosa 7stem-anatomy7 #ib #dag4 ,medullosa centrofilis #if #dah4 ,myeloxylon radiatum2 ,medullosa stellata2 ,m4 ,leuckarti #ajc #dai4 ,medullosa ,leuckarti #ajd #dbj4 ,myeloxylon radiatum2 ,medullosa anglica1 and ,medullosa sp4 #ajg #dba4 ,potoniea adiantiformis2 ,linopteris obliqua2 ,neuropteris heterophylla #aaa #dbb4 ,neuropterocarpus ,kidstoni4 ,edinburgh ,royal ,society4 #aad #dbc-dbf4 ,trigonocarpus ,parkinsoni #aah1 #abj1 #aba #dbg4 ,codonotheca caduca4 ,new ,phytologist4 #abe #dbh4 ,whittleseya elegans2 ,w4 brevifolia #abh #dbi4 ,whittleseya elegans #acj #dcj-dcb4 ,dolerophyllum ,goepperti #acc1 #acd1 #acg #dcc4 ,ottokaria bengalensis4 ,indian ,geol4 ,survey4 #adj #dcd4 ,strobilites ,milleryensis #ada #dce1 #dcf4 ,colpoxylon aeduense #adc #dcg1 #dch4 ,rhexoxylon africanum #adf1 #adh #dci1 #ddj4 ,sutcliffia insignis #aej1 #aea #dda4 ,steloxylon ,ludwigii #afc #ddb4 ,pecopteris ,pluckeneti #afg #ddc4 ,eremopteris artemisaefolia2 ,samaropsis acuta #agj #ddd4 ,samaropsis acuta4 ,r4 ,kidston #aga #dde4 ,wardia fertilis #agb #ddf-ddh4 ,megaloxylon ,scotti4 ,camb4 ,phil4 ,soc4 #agf-agh #ddi1 #dej4 ,rhetinangium ,arberi4 ,w4 ,t4 ,gordon #ahb #dea4 ,stenomyelon tuedianum #ahc #deb4 ,stenomyelon tuedianum4 ,r4 ,kidston #ahe #dec4 ,ptychoxylon ,levyi2 ,cycadoxylon ,fremyi2 ,c4 robustum #ahh #ded1 #dee4 ,calamopitys ,saturni4 ,m4 ,zalessky #aia1 #aib #def4 ,kalymma grandis #aie #deg4 ,eristophyton fasciculare #aig #deh4 ,eristophyton ,beinertianum4 ,m4 ,zalessky #aii #dei4 ,cladoxylon mirabile2 ,c4 dubium2 ,c4 taeniatum2 ,syncardia pusilla #bjb #dfj4 ,cladoxylon ,kidstoni2 ,c4 mirabile #bjf #dfa4 ,vlkelia refracta #bji #dfb4 ,protopitys ,buchiana #baa #dfc4 ,poroxylon ,edwardsii4 ,c4 ,e4 ,bertrand and ,f4 ,w4 ,oliver #baf #dfd4 ,poroxylon ,edwardsii2 ,p4 ,boysseti4 ,c4 ,e4 ,bertrand #bah #dfe4 ,cordaites leaf4 7,c4 ,felicis47 ,r4 ,kidston #bbh #dff4 ,cordaites principalis2 ,artisia transversa4 ,r4 ,kidston #bca #dfg4 ,cordaites lingulatus #bcd #dfh4 ,cordaites 7,rhizo-,cordaites72 ,cordaites circularis2 ,cordaites sp4 cf4 ,c4 ,lacoei2 ,c4 crassifolius #bcg #dfi4 ,cordaites aequalis2 ,c4 ,clerci4 ,m4 ,zalessky #bci #dgj4 ,cordaites 7,noeggerathiopsis7 ,hislopi4 ,g4 ,r4 ,wieland4 #bda #dga4 ,cordaites 7,noeggerathiopsis7 ,hislopi4 ,geological ,society4 #bda #dgb4 ,cordaites 7,noeggerathiopsis7 ,hislopi4 ,geol4 ,surv4 ,india4 #bdb #dgc4 ,cordaites stem #bdf #dgd1 #dge4 ,dadoxylon materiarum #beg #dgf4 ,dadoxylon ,pedroi #bei #dgg4 ,cordaites root #bfb #dgh4 ,cordaites8 root4 ,t4 ,n4 ,leslie #bfc #dgi4 ,cordaianthus4 ,f4 ,e4 ,weiss #bfe #dhj4 ,cordaianthus ,pitcairniae2 ,c4 ,volkmanni #bff #dha4 ,cordaianthus ,grand',euryi2 ,c4 ,williamsoni2 ,c4 ,zeilleri4 ,c4 ,e4 ,bertrand #bfh #dhb4 ,cordaianthus microsporangia #bgj #dhc4 ,mesoxylon ,sutcliffii #bgb #dhd4 ,pelourdea vogesiaca4 ,geologists' ,assoc4 #bgi #dhe4 ,titanophyllum ,grand',euryi #bhd #dhf1 #dhg4 ,pitys antiqua #bhf1 #bhg #dhh4 ,pitys primaeva #bhh #dhi4 ,callixylon ,trifilievi4 ,m4 ,zalessky #bib #dij4 ,mesopitys ,tchihatcheffi #bif #dia4 ,antarcticoxylon ,priestleyi #bih #dib4 ,diagram of a synthetic type of seed #cjc #dic4 ,lagenostoma ovoides2 ,l4 ,lomaxi2 ,physostoma elegans2 ,telangium ,scotti2 ,stephanospermum akenioides #caa #did4 ,stephanospermum akenioides2 ,conostoma oblonga2 ,gnetopsis elliptica2 ,physostoma elegans2 ,mitrospermum compressum #cad #die4 ,polypterospermum ,renaultii2 ,ptychotesta tenuis2 ,polylophospermum stephanense2 ,hexapterospermum stenopterum2 ,diplotesta avellana2 ,d4 ,grand',euryana2 ,taxospermum ,grneri #cbb #dif4 ,pachytesta incrassata2 ,polypterocarpus anglicus #cbd #dig4 ,pachytesta #cbe #dih4 ,codonospermum olivaeforme2 ,aetheotesta elliptica #ccj #dii4 ,samaropsis emarginata #ccg #ejj4 ,cardiocarpus drupaceus var4 expansus #cci #eja4 ,cardiocarpus sclerotesta2 ,rhabdocarpus cyclocaryon #cdj #ejb4 ,samaropsis fluitans2 ,s4 emarginata2 ,s4 bicaudata2 ,s4 ,seixasi2 ,s4 barcellosa2 ,s4 ,newberryi2 ,cordaicarpus ,cordai #cej #ejc4 ,samaropsis ,leslii #ceb #ejd4 ,samaropsis ,milleri4 ,geol4 ,surv4 ,india4 #cec #eje4 ,cordaicarpus ,cordai #cee #ejf4 ,holcospermum sulcatum2 ,codonospermum anomalum2 ,diplopterotesta spitzbergensis2 ,gnetopsis elliptica2 ,thysanotesta sagittula2 ,rhynchogonium costatum2 ,boroviczia ,karpinskii2 ,hexagonocarpus ,noeggerathi2 ,rhabdospermum tunicatum #cei #ejg4 ,cycadeoidea marylandica4 ,g4 ,r4 ,wieland4 #cgc #ejh1 #eji4 ,cycadeoidea ,wielandi ,g4 ,r4 ,wieland4 #cge1 #cgf #eaj4 ,cycadeoidea sp4 #cgg #eaa4 ,cycadeoidea ,gibsoniana #cgg #eab4 ,cycadeoidea ingens4 ,g4 ,r4 ,wieland4 #cgh #eac-eae4 ,cycadeoidea4 ,g4 ,r4 ,wieland4 #chj-chc #eaf4 ,cycadeoidea ,dartoni #chd #eag-ebc4 ,cycadeoidea ,gibsoniana #chg-cid #ebd-ebg4 ,cycadeoidea 7,bennettites7 ,morierei4 ,o4 ,lignier4 #cig-djb #ebh-ecb4 ,cycadeoidea dacotensis4 ,g4 ,r4 ,wieland4 #djd-djh #ecc4 ,cycadeoidea colossalis4 ,g4 ,r4 ,wieland4 #daj #ecd4 ,cycadeoidea ,reichenbachiana4 ,a4 ,rothpletz4 #daa #ece-ecg4 ,cycadeoidea gigantea4 ,geological ,soc4 #dac1 #dad #ech4 ,cycadeoidea micromyela #dae #eci4 ,cycadeoidea ,jenneyana 787 ,g4 ,r4 ,wieland4 #daf #edj4 ,vectia luccombensis4 ,trustees of the ,british ,museum4 #dai #eda-edc4 ,williamsonia gigas #dbd-dbg #edd4 ,williamsonia gigas4 ,yorkshire ,nat4 ,union4 #dbh #ede4 ,williamsonia gigas4 ,a4 ,g4 ,nathorst4 #dbi #edf1 #edg4 ,williamsonia gigas #dcj1 #dca #edh4 ,williamsonia gigas4 ,o4 ,lignier4 #dcb #edi1 #eej4 ,williamsonia gigas4 ,cambridge ,phil4 ,soc4 #dce1 #dcf #eea4 ,williamsonia spectabilis4 ,a4 ,g4 ,nathorst4 #dcg #eeb4 ,williamsonia spectabilis4 ,geological ,soc4 #dch #eec1 #eed4 ,williamsonia ,leckenbyi4 ,a4 ,g4 ,nathorst4 #dci1 #ddj #eee1 #eef4 ,williamsonia whitbiensis4 ,a4 ,g4 ,nathorst4 #dda #eeg4 ,williamsonia sp4 ,indian ,geol4 ,survey4 #ddd #eeh4 ,williamsonia ,blandfordi4 ,indian ,geol4 ,survey4 #ddf #eei4 ,williamsonia ,carruthersi #ddg #efj4 ,williamsonia ,bucklandi #ddi #efa4 ,williamsonia scotica #dej #efb-efd4 ,williamsonia scotica4 ,royal ,society4 #dea-dec #efe4 ,williamsonia spectabilis2 ,w4 whitbiensis2 ,w4 mexicana #dei #eff1 #efg4 ,wielandiella angustifolia #dfc1 #dfd #efh4 ,wielandiella angustifolia4 ,a4 ,g4 ,nathorst4 #dff #efi-egc4 ,williamsoniella coronata4 ,royal ,society4 #dfh-dga #egd4 ,cycadocephalus ,sewardi4 ,a4 ,g4 ,nathorst4 #dgd #ege4 ,bucklandia anomala #dhb #egf4 ,bucklandia ,milleriana #dhd #egg4 ,bucklandia ,yatesii #dhe #egh4 ,bucklandia buzzardensis4 ,trustees of the ,british ,museum4 #dhf #egi4 ,bucklandia indica4 ,trustees of the ,british ,museum4 #dhh #ehj1 #eha4 ,colymbetes ,edwardsi #dib1 #dic ,trustees of the ,british ,museum4 #ehb1 #ehc4 ,cycadolepis sp4 #die #ehd1 #ehe4 ,carpolithus conicus #dih ,trustees of the ,british ,museum4 #ehf4 ,beania gracilis4 ,w4 ,g4 ,carruthers4 #ejb #ehg4 ,ptilophyllum pecten4 ,trustees of the ,british ,museum4 #eac #ehh1 #ehi4 ,ptilophyllum pecten #ead1 #eaf ,geological ,surv4 ,india4 #eij4 ,ptilophyllum pecten and ,williamsonia ,blandfordi #eag ,geological ,surv4 ,india4 #eia4 ,ptilophyllum cutchense4 ,geological ,society4 #eah #eib4 ,ptilophyllum pecten #eai #eic4 ,ptilophyllum pecten4 ,geological ,society4 #eai #eid4 ,ptilophyllum pecten #ebj #eie4 ,ptilophyllum pecten #ebc #eif4 ,ptilophyllum pecten4 ,trustees of the ,british ,museum4 #ebc #eig4 ,ptilophyllum boreale4 ,a4 ,g4 ,nathorst4 #ebf #eih4 ,ptilophyllum antarcticum2 ,p4 ,anderssoni #ebg #eii4 ,zamites gigas4 ,encyclopaedia ,britannica4 #ecc #fjj4 ,zamites recta #ecd #fja4 ,zamites ,buchianus2 ,z4 ,carruthersi2 ,z4 ,zitteli #ece #fjb4 ,zamites ,buchianus #ecf #fjc4 ,otozamites ,goeppertianus2 ,o4 ,bechei #ech #fjd4 ,otozamites ,bechei #eci #fje4 ,otozamites ,bechei #eda #fjf4 ,otozamites ,beani2 ,o4 ,bunburyanus ,encyclopaedia ,britannica4 #edb #fjg4 ,otozamites bengalensis4 ,geological ,surv4 ,india4 #edb #fjh4 ,otozamites ,kliptsteini4 ,geological ,society4 #ede #fji4 ,dictyozamites ,hawelli #edh #faj4 ,pterophyllum ,jaegeri #edi #faa4 ,pterophyllum ,nilssoni2 ,nilssonia mediana #eea #fab4 ,pterophyllum ,fayoli #eeb #fac4 ,pterophyllum ,braunianum #eed #fad4 ,pterophyllum ,nathorsti2 ,nilssonia tenuicaulis #eef ,royal ,society of ,scotland4 #fae4 ,pterophyllum ,nilssoni ,trustees of the ,british ,museum4 #eeg #faf4 ,pterophyllum ,lyellianum ,trustees of the ,british ,museum4 #eeg #fag4 ,pseudocycas insignis #efb #fah4 ,pseudocycas ,saportae4 ,encyclopaedia ,britannica4 #efd #fai4 ,nilssonia pterophylloides2 ,n4 brevis2 ,n4 polymorpha #efg #fbj4 ,nilssonia brevis2 ,n4 saighensis #egj #fba4 ,nilssonia rajmahalensis4 ,geological ,surv4 ,india4 #ega #fbb4 ,nilssonia compta4 ,trustees of the ,british ,museum4 #egd #fbc4 ,nilssonia princeps4 ,geological ,surv4 ,india4 #egg #fbd1 #fbe4 ,ctenis sp4 ,manchester ,phil4 ,lit4 ,society4 #egi #fbf4 ,ctenis sulcicaulis #ehc #fbg4 ,pseudoctenis eathiensis ,trustees of the ,british ,museum4 #ehd #fbh4 ,sphenozamites ,rochei #ehh #fbi4 ,sphenozamites ,belli4 ,trustees of the ,british ,museum4 #ehh ,,chapter ,,xxviii4 ,,cycadales 7recent74 ,among the fossil genera described in the last chapter of the second volume some were spoken of as true ,ferns though most of them1 it was added1 #8may safely be regarded as plants which will ultimately be shown to belong to some other group1 in most cases that of the ,pteridosperms4' ,since this was written additional evidence has been obtained in favour of the inclusion of certain genera in the ,pteridosperms4 ,in the case of ,taeniopteris1 one of the genera already described1 there is reason to believe that at least one species is a member of the ,cycadales and not a true ,fern as formerly supposed4 ,the ,pteridosperms so far described are represented for the most part by sterile leaves preserved as impressions1 the genera founded on more satisfactory material having been reserved for treatment in this volume4 ,as these genera are founded to a large extent on anatomical characters oscillating in their essential features between recent ,ferns and ,cycads1 it is important that the student should be in possession of the anatomical characteristics of both of these classes2 and for this reason a general account of recent ,cycads is intercalated between the ,pteridosperms already described and those reserved for treatment in this volume4 99 99 99 99 99 ,the section of the ,gymnosperms known as the ,cycadales1 represented by nine recent genera and less than #ajj species1 is of exceptional importance phylogenetically and demands special attention from palaeobotanical students4 ,familiarity with the morphology of recent forms is essential not only in relation to extinct cycadean plants but also to types which1 though not sufficiently close to surviving species to be included with them in one class1 exhibit features regarded by many botanists as indications of an affinity either to true ,cycads or to some generalised stock of which they are an offshoot4 ,the ,cycads of to-day may fairly be spoken of as anachronisms1 plants appropriate to a former age but out of harmony with the present4 ,they are confined to tropical and sub-tropical regions in both the old and new world4 ,in habit many of them resemble tree-ferns1 but the columnar stem1 which may live to a great age and attain a height of #bj metres1 differs from that of ferns in its gradually tapered form consequent on the presence of one or more cambial cylinders4 ,though often unbranched 7fig4 #cgg7 branching of the main trunk is by no means unusual 7fig4 #cgh2 fig4 #cha1 ,b74 ,many ,cycads are geophilous and have short tuberous stems 7figs4 #chc1 #cie1 #a;a2 #cif1 ,e73 the genus ,zamia includes a few epiphytic forms#a4 ,the typical cycadean stem is covered with persistent petiole-bases with or without an admixture of smaller scale-leaf bases 7figs4 #cgi1 #chj71 while in several species a transversely wrinkled or irregularly fissured periderm forms the superficial tissue 7figs4 #cha1 ,b2 #chc74 ,the foliage-leaves are relatively large and1 with the exception of the bipinnate fronds of ,bowenia 7fig4 #cia71 they are always pinnate4 ,the fronds usually form a terminal crown 7figs4 #cgg1 #cgi7 and as many as #ajj may be produced from one bud4 ,in ,zamia pygmaea#b the fronds are only #aj-ab cm4 long1 but in some cycads they reach a length of several metres4 ,on both young foliage-leaves and scale-leaves long and very rarely branched#c unicellular hairs 7fig4 #cif1 ,n7 form a characteristic feature and take the place of the ramental scales of the majority of ferns4 ,the apex of the stem shown in fig4 #chf1 ,a is covered with a mass of woolly hairs and several scale-leaves are seen on the lower part of the bud4 ,illustration3 ,fig4 #cgg4 ,cycas circinalis4 ,from a photograph taken by ,mr ,a4 ,malins ,smith at ,teldeniya 7,ceylon74 ,illustration3 ,fig4 #cgh4 ,cycas revoluta1 as grown by ,japanese horticulturalists4 7,after ,wieland47 ,illustration3 ,fig4 #cgi4 ,encephalartos horridus4 ,illustration3 ,fig4 #chj4 ,cycas circinalis4 ,stem showing alternate zones of leaf-bases 7,f7 and scale-leaf bases 7,s74 7,from the ,encyclopaedia ,britannica47 ,illustration3 ,fig4 #cha4 ,a4 ,cycas revoluta1 megasporophylls4 ,b4 ,zamia ,loddigesii1 branched stem4 ,all recent ,cycads are dioecious4 ,the reproductive shoots1 except the megasporophylls of ,cycas--which have departed to a less extent than those of other genera from the foliage-leaf plan 7fig4 #cha1 ,a2 fig4 #cib1 ,a-,c7 and are borne in a terminal cluster through which the stem subsequently pushes its way--consist of a varying number of micro- or mega-sporophylls in dense spirals on the axis of an elongated or oval strobilus 7figs4 #chf1 ,b1 #cic1 #cid74 ,the microsporophylls are occasionally verticillate#d4 ,the strobili are sometimes though rarely branched#e and generally but by no means invariably#f terminal on the main stem which branches sympodially#g4 ,a striking example of lateral strobili has recently been described by ,chamberlain#h who figures a stem of ,macrozamia ,moorei with fertile shoots wedged among the persistent petiole-bases1 a condition very similar to that in the ,mesozoic ,bennettitales4 ,pearson has also described clear cases of laterally-borne cones in ,encephalartos4 ,cycas exhibits two kinds of branching1 the female plants being monopodial while in the male the branching is sympodial4 ,the microspores are produced in sporangia grouped in more or less well defined sori 7figs4 #chi1 ,a2 #cib1 ,e-,g74 ,there is no definite annulus1 but in the occurrence of groups of thick-walled cells some microsporangia recall those of certain ferns#i4 ,the ovules vary considerably in size1 sometimes exceeding #e cm4 in diameter3 there are usually two on each megasporophyll 7figs4 #cic1 ,c2 #cid2 #cie1 #a;d7 but in most species of ,cycas 7fig4 #cib1 ,b7 and occasionally in other genera the number is larger#aj4 ,a thick integument encloses the nucellus with which it is fused except in the apical region 7fig4 #cif1 ,a1 ,b74 ,below the comparatively long micropylar tube is a well-developed pollen-chamber 7fig4 #cif1 ,b1 p71 a striking feature of ,cycadean ovules1 immediately above the megaspore2 the latter is filled with prothallus-tissue and bears a small apical group of archegonia on the floor of a depression 7fig4 #cif1 ,a-,b74 ,in ,microcycas#aa as many as #bjj archegonia are recorded--a very exceptional case--and these are not confined to the apical region1 though only the apical archegonia are functional4 ,each archegonium is characterised by a very large oval egg-cell and a much reduced neck#ab4 ,the microspores usually produce a single prothallus-cell1 a stalk-cell1 and body-cell1 and from the body-cell are developed two spirally ciliated spermatozoids 7fig4 #cif1 ,m74 ,in this respect also the monotypic genus ,microcycas is peculiar3 it may have as many as #h body-cells and #af male gametes in a single pollen-tube 7fig4 #cif1 ,g71 while in ,ceratozamia#ac #d gametes have been seen in one tube4 ,the pollen-tube grows like a fungal mycelium into the nucellar tissue and the male gametes are formed in the distended proximal end which on bursting liberates the motile sperms with the watery cell-sap4 ,fertilisation is succeeded by the development of a homogeneous proembryo partially or completely filling the zygote 7fertilised egg73 by the formation of long suspensors the embryo is brought into contact with the food-store of the prothallus4 ,in some ,cycads1 e4g4 ,encephalartos1 the embryogeny exhibits a close resemblance to that of ,ginkgo#ad4 ,the embryo is dicotyledonous#ae4 ,the single stele of the stem is characterised by a large pith which in some genera 7e4g4 ,encephalartos1 ,macrozamia7 contains an anastomosing system of collateral bundles4 ,the vascular tissue of a cycadean stem forms a cylinder of secondary xylem and phloem1 the primary xylem being represented only by a few1 usually crushed1 protoxylem elements on the inner margin of the reticulately pitted or scalariform tracheids4 ,both xylem and phloem are traversed by numerous broad and deep medullary rays#af4 ,the looser texture and more parenchymatous structure of ,cycadean wood afford a ready means of distinguishing it from the wood of ,conifers3 for the ,cycadean type the term manoxylic is proposed and pycnoxylic for the more compact coniferous wood#ag4 ,rims 7or #8bars'7 of ,sanio1 of which much has been said in discussions on the phylogeny of ,conifers1 have recently been described in the petiolar xylem of ,cycas revoluta3 the rims are short and #8cling closely to the borders of the pits1' features which also characterise the rims found in the cones of the ,araucarineae and in the root- and cone-wood of certain ,pines#ah4 ,in some ,cycads the secondary xylem and phloem form a single cylinder1 but in others 7,cycas1 ,encephalartos1 ,macrozamia1 ,bowenia7 the cambium is succeeded by one or several concentric cylinders of meristem which have their origin in the pericycle4 ,the spasmodic occurrence of separate arcs of inversely orientated secondary xylem and phloem between the normal cylinders is a feature of importance from the point of view of comparison with the ,palaeozoic ,medulloseae#ai4 ,the occurrence of concentric cauline strands in the cortex of ,cycas is also a peculiarity worthy of notice4 ,successive bands of periderm1 and occasionally a considerable amount of phelloderm#bj1 are formed in the peripheral region of the stem4 ,the leaf-traces in an adult stem exhibit a striking feature in their indirect or girdle-like course to the leaves 7fig4 #cif1 ,h1 g7 and in the gradual change from an endarch 7fig4 #cif1 ,o7 to an apparently mesarch structure 7fig4 #djj7 as they pass from the perimedullary zone to the petiole3 except at the base of the petiole the vascular bundles of the frond-axis consist of 7i7 centripetally developed xylem with a median protoxylem and a much smaller amount of centrifugal xylem 7fig4 #djj7 separated by a few parenchymatous elements from the centripetal xylem1 7ii7 an external arc of protophloem and within this metaphloem and parenchyma#ba4 ,in the slender petiole of ,bowenia there are a few collateral bundles arranged in the form of a circle or ellipse#bb2 in ,cycas and some other genera the more numerous bundles form a pattern like an inverted ,u1 and in some species of ,encephalartos the number is greater and the strands more irregularly scattered#bc4 ,in the vegetative stems there is no centripetal xylem in the stele1 but scattered centripetal tracheids occasionally occur internal to the protoxylem in the steles of the peduncles#bd4 99 99 99 99 99 ,cycadeae4 ,megasporophylls each bearing #b-h ovules1 borne separately like foliage-leaves and not in strobili4 ,pinnae have a midrib but no lateral veins 7figs4 #chd1 #chg1 ,a74 ,cycas 7fig4 #cgg74 ,zamieae4 ,both kinds of sporophylls form strobili4 ,pinnae have several dichotomously branched1 more or less parallel veins4 ,zamia 7figs4 #chh-cij71 ,macrozamia1 ,encephalartos 7figs4 #cgi1 #chf1 ,c71 ,ceratozamia1 ,dioon 7fig4 #chf1 ,b71 ,microcycas4 ,stangerieae4 ,strobili as in ,zamieae4 ,pinnae fern-like1 numerous dichotomously branched lateral veins given off from a midrib4 ,stangeria4 ,bowenieae4 ,leaves bipinnate 7fig4 #cia71 strobili as in ,zamieae4 ,bowenia4 ,distribution4 ,the most widely spread genus1 ,cycas1 occurs in ,siam1 ,india1 the ,nicobar ,islands1 ,ceylon1 ,madagascar1 and ,australia1 in many of the islands in the ,indian and ,pacific oceans1 in ,new ,guinea1 ,borneo1 ,new ,caledonia1 ,new ,britain1 ,china and ,japan#be4 ,zamia1 the most northerly genus1 extends from ,north ,mexico and ,florida through ,central ,america and some of the ,west ,indian islands to ,ecuador1 ,bolivia1 ,chile1 and ,peru4 ,dioon and ,ceratozamia are confined to ,south ,mexico1 and ,microcycas flourishes on the ,cuban mountains4 ,the continent of ,africa possesses two endemic genera ,encephalartos and ,stangeria4 ,encephalartos extends from ,cape ,colony through ,natal and ,zululand to ,zanzibar and ,mombasa#bf3 a specimen in the ,kew ,herbarium 7probably ,e4 ,hildebrandti7 is said to have been collected as far north as the ,soudan4 ,two species are recorded from the ,congo#bg and ,e4 ,barteri1 discovered by ,barter in ,central ,africa1 is recorded from the ,gold ,coast#bh4 ,stangeria has a much more limited range in ,s4,e4 ,africa#bi2 ,australia possesses ,macrozamia1 represented by several species in ,western ,australia1 ,new ,south ,wales and ,queensland1 ,cycas in ,queensland and the ,northern territory and the ,queensland genus ,bowenia4 ,there are no ,cycads in ,new ,zealand4 ,as a whole ,cycads have a limited range and with the exception of ,cycas and ,zamia none of them extend beyond the limits of a single continent4 ,they are as a rule not gregarious plants and play a subordinate part in the facies of the vegetation4 ,macrozamia forms dense thickets#cj in some districts and occurs both in exposed situations and in association with ,palms in damp ,queensland forests4 ,chamberlain#ca speaks of #ajj plants of ,dioon edule as visible in one view in ,south ,mexico where the species forms a mountain forest4 ,in ,florida ,zamia pumila#cb grows in dense moist woods1 a habitat in contrast to that of many ,cycads4 ,the ,mexican ,ceratozamia is associated with luxuriant vegetation1 while its compatriot ,dioon#cc lives in blazing sunshine4 ,sir ,joseph ,hooker#cd speaks of ,cycas living in the deepest and hottest valleys in ,sikkim4 ,encephalartos is essentially a xerophilous genus4 ,stangeria paradoxa is said to be confined to forests in ,cape ,colony1 and another species grows among the grass of the ,park-lands in open country#ce4 ,while it is true that many ,cycads are characteristic of dry regions some species flourish in places where shade and moisture are abundant4 ,though it is impossible in many cases to form an estimate of the age of individual plants1 there are clear indications that some specimens afford notable instances of longevity4 ,chamberlain estimates the age of some plants of ,dioon spinulosum as exceeding #djj years and mentions an example of ,d4 edule that is probably #ajjj years old4 ,an unusually tall plant of ,encephalartos in the ,botanic ,garden of ,amsterdam is believed by ,prof4 de ,vries to have reached the venerable age of #bjjj years#cf4 ,the restricted range and in many cases the solitary existence of recent ,cycads1 with their tall stems clothed with the persistent cork-covered stumps of thousands of fronds1 deepens the impression of antiquity derived from a study of the geological history of this dwindling race4 ,stems4 ,the tall columnar stems of some species of ,cycas1 often branched or bearing numerous ovoid buds like enlarged bulbils#cg1 are characterised by the regular alternation of large and small leaf-bases as seen in the stem of ,c4 circinalis reproduced in fig4 #chj4 ,in older stems of this species the leaf-bases are exfoliated and the stem is covered with wrinkled and fissured cork2 but in ,cycas revoluta the leaf-bases are even more persistent4 ,the columnar but relatively stout stems of ,encephalartos 7figs4 #cgi1 #chb1 #chf1 ,a7 and ,ceratozamia are similarly encased in a covering of petiole-bases1 but in these genera the differences between foliage-leaves and bud-scales is much less obvious and there is no zonal alternation4 ,on the stems of ,macrozamia the rhomboidal leaf-bases are more uniform in size and there are no scale-leaves4 ,the tall and often palm-like stems of ,microcycas sometimes show transverse rings on the bark marking the position of former terminal buds1 and in older trunks these may disappear1 leaving a fissured bark#ch4 ,in ,cycas siamensis the tuberous stem is similarly covered with a rough bark 7fig4 #chc7 and the stems of ,zamia are also characterised by an absence of persistent leaf-bases 7figs4 #cha1 ,b2 #cie1 ,ia1 a74 ,it is pertinent to remind the palaeobotanical student of the occurrence of flowering plants with stems closely simulating those of some ,cycads4 ,prof4 ,bower#ci in describing ,rhynchopetalum montanum1 an ,abyssinian ,lobeliaceous plant1 drew attention to the similarity in surface-features and to some extent in anatomical structure to cycadean stems4 ,the resemblances are further emphasised in a more recently published account of the same species under a different name1 ,lobelia ,rhynchopetalum#dj4 ,illustration3 ,fig4 #chb4 ,encephalartos ,ghellinckii4 7 nat4 size47 ,illustration3 ,fig4 #chc4 ,cycas siamensis4 7,from the ,encyclopaedia ,britannica47 ,fronds4 ,a general acquaintance with the various types of fronds illustrated by recent ,cycads is important to the student of fossils not only to enable him to compare existing and extinct forms but as affording safeguards against possible sources of error in the description and identification of impressions#da4 ,the vernation exhibits less uniformity than in ,ferns3 in ,cycas the rachis is straight and the pinnae circinately coiled 7fig4 #bbj1 ,b1 vol4 ii4 p4 #bhc72 in ,zamia and ,stangeria the rachis is bent and the pinnae straight1 while in ,ceratozamia and other genera both the axis and leaflets are straight4 ,as ,braun pointed out1 there is as a rule no terminal leaflet1 or it may be pushed to one side giving a forked appearance to the frond apex#db4 ,illustration3 ,fig4 #chd4 ,cycas circinalis1 abnormal frond4 7,from a specimen in the ,british ,museum47 ,cycas4 ,the presence of a strong midrib and the absence of lateral veins are distinguishing features3 the lower margin of the lamina is frequently decurrent 7fig4 #chg1 ,a74 ,in ,c4 circinalis the pinnae may reach #dj cm4 in length with a fairly uniform breadth of #b cm4 ,a frond of this species in the ,british ,museum1 not quite complete1 has a length of #aab cm43 on the lower part of the rachis strong spines replace the leaflets and near the apex of the leaf concrescent pinnae form a continuous lamina traversed by seven ribs and dissected at the margin into acuminate teeth 7fig4 #chd73 some of the pinnae are forked as in ,cycas ,micholitzii#dc 7fig4 #che74 ,several years ago ,i noticed a similar instance of concrescence in a small plant of ,c4 circinalis in the ,royal ,gardens1 ,kew 7fig4 #chg1 ,i74 ,in ,cycas ,micholitzii the pinnae1 reaching a length of #bj cm41 are repeatedly and deeply forked 7fig4 #che1 ,a1 ,b2 fig4 #djj73 the pinnae of ,c4 ,rumphii var4 bifida#dd are also deeply dissected4 ,cycas ,beddomei has very narrow pinnae 7#ae cm4 #b mm47 similar to those of the ,wealden species ,cycadites ,saportae1 and it is noteworthy that narrow leaflets with a strongly revolute lamina would produce casts with two parallel ribs 7the grooves between the midrib and the edge of the lamina7 simulating the double midrib of the fossil genus ,pseudocycas4 ,in some fronds1 e4g4 ,c4 ,cairnsiana1 the midrib is hardly visible on the upper face of a dried pinna which shows a longitudinal wrinkling simulating parallel venation4 ,illustration3 ,fig4 #che4 ,a1 ,b1 ,cycas ,micholitzii4 7,after ,thiselton-,dyer47 ,c1 ,zamia angustifolia4 ,encephalartos4 ,the fronds of this genus1 in ,encephalartos ,laurentianus#de reaching the exceptional length of #g metres1 bear alternate pinnae exhibiting a considerable range in form and breadth4 ,in ,e4 longifolius1 ,e4 ,altensteinii 7fig4 #chf1 ,c71 ,e4 ,lehmanni1 etc41 the pinnae are for the most part linear1 reaching a length of #bj cm4 and a breadth of #b cm43 in ,e4 caffer 7fig4 #chg1 ,d71 ,e4 latifolius1 and others the pinnae are broader and shorter and often spinous4 ,a frond of ,e4 longifolius or ,e4 ,altensteinii may bear both entire and lobed1 spinous pinnae4 ,in ,e4 ,frederici-,guilielmi 7fig4 #chg1 ,g7 and ,e4 ,ghellinckii#df 7fig4 #chb7 the pinnae are very narrow and almost filiform1 with revolute edges4 ,the thick and leathery pinnae of some species are attached obliquely to the edge or to the upper sloping sides of the rachis which forms a prominent ridge between the rows of leaflets1 and characteristic oval scars are left on the fall of the pinnae 7fig4 #chg1 ,d1 ,g74 ,the lamina in most species contains several veins more or less parallel to the margins and often much more prominent on the lower than on the upper surface4 ,illustration3 ,fig4 #chf4 ,a4 ,encephalartos ,altensteinii1 apex of stem4 ,b4 ,dioon edule1megastrobilus4 7,from a photograph by ,mr ,s4 ,m4 ,wadham47 ,c4 ,encephalartos ,altensteinii1 frond4 ,illustration3 ,fig4 #chg4 ,cycadean fronds4 ,a1 ,cycas circinalis2 ,b1 ,macrozamia ,fraseri2 ,c1 ,macrozamia ,denisoni2 ,d1 ,encephalartos caffer2 ,e1 ,f1 ,dioon edule from below and above2 ,g1 ,encephalartos ,frederici-,guilielmi1 ,g1 side-view2 ,h1 ,ceratozamia mexicana2 ,i1 ,cycas circinalis1 lower part of young frond4 ,zamia4 ,in ,zamia angustifolia 7fig4 #che1 ,c7 and ,z4 linifolia the pinnae are long and very narrow3 the other extreme is represented by ,z4 ,wallisii#dg 7fig4 #chh7 with broad ovate segments reaching a length of nearly #e metre and attached to the rachis by a short stalk2 the veins are prominent and dichotomously branched4 ,other forms of pinnae are represented by ,z4 integrifolia1 ,z4 floridana1 and ,z4 ,loddigesii 7figs4 #chi1 #cij1 #cie74 ,the broad and short pinnae of ,z4 furfuracea#dh bear a close resemblance1 except in the absence of an auriculate base1 to those of some species of the fossil genus ,otozamites4 ,the broadly linear pinnae of ,z4 pseudoparasitica 7#de cm4 #c cm47 often show longitudinal wrinklings on drying which suggest comparison with the corrugated lamina of the fossil species ,nilssonia brevis4 ,a basal pad or callosity on the slender bases of the pinnae is characteristic of many ,zamia fronds4 ,illustration3 ,fig4 #chh4 ,pinna of ,zamia ,wallisii4 ,from a drawing after ,a4 ,braun in the ,kew ,herbarium4 7 nat4 size47 ,illustration3 ,fig4 #chi4 ,zamia integrifolia bearing a megastrobilus and showing foliage-leaves and scale-leaves4 ,a1 microsporophyll2 ,b1 megasporophyll4 7,after ,rendle1 from ,jacquin47 ,illustration3 ,fig4 #cij4 ,small frond of ,zamia ,loddigesii4 7 nat4 size47 ,ceratozamia4 ,the fronds bear a fairly close resemblance to those of ,macrozamia3 in ,ceratozamia mexicana the linear pinnae reach a length of over #cj cm4 and a breadth of #b-c cm42 the lamina tapers to a narrow apex and is more abruptly contracted at the base 7fig4 #chg1 ,h74 ,the veins in ,ceratozamia are sub-parallel and dichotomy occurs up to the middle of the lamina#di4 ,a striking feature is the occurrence of two opposite stipule-like projections a short distance above the base of the petiole4 ,macrozamia4 ,a noteworthy feature in some species is the attachment of the linear pinnae along the middle line of the rachis 7fig4 #chg1 ,c72 in others 7fig4 #chg1 ,b7 the leaflets are attached laterally and may have a basal callosity4 ,the parallel veins1 which branch dichotomously near the base of the lamina1 are often much more prominent on the lower than on the upper face4 ,in ,m4 heteromera#ej 7fig4 #cif1 ,f1 ,f7 the narrow pinnae are deeply forked and strongly revolute4 ,the spirally twisted rachis of ,m4 spiralis1 ,m4 heteromera1 etc41 is a striking feature recalling the ,rhaetic fern ,camptopteris spiralis ,nath#ea4 ,dioon4 ,the arrangement of the linear pinnae of ,d4 edule 7fig4 #chf1 ,b71 ,d4 spinulosum1 and ,d4 ,purpusii#eb forms a ready means of distinguishing the fronds of this genus3 the pinnae1 often contiguous and at right-angles to the rachis1 are attached in a lateral groove by an expanded and slightly decurrent base4 ,the difference between the lower and upper face of a frond 7fig4 #chg1 ,e1 ,f7 affords a good illustration of a common source of error in the identification of fossil specimens4 ,the leaflets of ,d4 spinulosum1 which except in their spinous margin are very similar to those of ,d4 edule1 may reach a length of #ae cm4 and a breadth of #h mm4 ,the parallel veins are unbranched#ec4 ,microcycas#ed4 ,the pinnae of this genus1 very like those of the ,wealden species ,zamites ,buchianus1 reach a length of #bj cm4 and a breadth of #h mm43 on falling they leave oblong scars resembling those on the rachis of ,encephalartos4 ,stangeria4 ,this genus is particularly interesting because of its fern-like habit and venation4 ,the large fronds of ,s4 paradoxa#ee bear broadly linear acuminate pinnae with entire1 unevenly lobed1 serrate1 or pinnatifid margins4 ,some leaflets are so deeply dissected as almost to justify the appellation pinnate4 ,both entire and dissected leaflets may occur on one frond and the lower ones may be stalked while the upper pinnae are sessile4 ,the venation agrees closely with that of the genus ,taeniopteris#ef4 ,bowenia4 ,the large fronds of this genus 7fig4 #cia7 are peculiar in being bipinnate2 they may reach a length of #b metres and have a long slender petiole3 the asymmetrical lamina of the segments1 entire or deeply serrate1 is attached by a very short stalk2 the veins branch dichotomously#eg and diverge slightly4 ,both entire and serrate pinnae may occur on the same plant1 but ,chamberlain has revived ,andr's specific term serrulata in preference to the generally adopted designation for the serrate forms1 ,b4 spectabilis var4 serrata#eh4 ,illustration3 ,fig4 #cia4 ,bowenia spectabilis1 frond4 7,from the ,encyclopaedia ,britannica47 ,reproductive shoots#ei4 ,in ,cycas circinalis1 ,c4 ,rumphii1 and other species the megasporophylls reach a considerable length and bear several lateral ovules each of which may be as large as a goose's egg3 the sterile distal end has the form of a spear-point with an irregularly serrate edge4 ,in ,c4 revoluta1 ,c4 pectinata1 etc41 the sterile part is deeply dissected and may break off 7fig4 #cib1 ,a7 from the fertile portion of the sporophyll4 ,the megasporophylls of ,c4 ,riuminiana exhibit a striking variation in form 7fig4 #cib1 ,b1 ,c72 some are #ae cm4 long with several ovules1 while others1 reduced to #h cm41 bear only two ovules and resemble the sporophylls of ,dioon4 ,in all other genera the megasporophylls are aggregated into cones1 but in ,dioon the strobili are characterised by their more ovoid form and by the looser arrangement of the sporophylls 7fig4 #chf1 ,b71 each of which consists of a horizontal stalk expanded distally into a broadly lanceolate upturned end covered with a thick felt of hairs and bearing at its base usually #b1 rarely #e-f1 ovules on cushion-like swellings4 ,in ,dioon spinulosum the cones may be #ej cm4 long4 ,between the cones of ,microcycas1 over #ij cm4 long1 and those of some ,zamias1 a few centimetres long1 there are many intermediate forms4 ,the large strobilus of an ,encephalartos reproduced in fig4 #cic1 ,d1 shows the convex ends of the sporophylls with a jagged edge1 and in monstrous cones the marginal lobes may be abnormally developed and assume the appearance of pinnae#fj4 ,each megasporophyll bears two large ovules 7fig4 #cic1 ,b74 ,in certain species of ,encephalartos the swollen ends of the sporophylls have a truncate centre like the flattened umbo of some ,pines 7fig4 #cib1 ,d74 ,the presence of two divergent spines is a peculiarity of the megasporophylls of ,ceratozamia 7fig4 #cic1 ,c73 in ,macrozamia 7fig4 #cid7 the distal ends are prolonged as tapered processes4 ,the surface of the strobilus of ,stangeria is formed by imbricate and rounded ends of sporophylls 7fig4 #cib1 ,h7 not unlike the cone-scales of ,pinus excelsa or ,p4 cembra4 ,the megasporophylls of ,zamia are expanded into regular cushion-like hexagons with a flat central area 7figs4 #chi1 ,b2 #cie1 ,ib74 ,illustration3 ,fig4 #cib4 ,a4 ,cycas pectinata1 apex of megasporophyll4 7 nat4 size47 ,b1 ,c4 ,cycas ,riuminiana1 megasporophyll4 7 nat4 size47 ,d4 ,encephalartos ,altensteinii4 ,distal end of megasporophylls4 7,from the ,gardeners' ,chronicle47 ,e1 ,f4 ,cycas angulata1 microsporophyll and sorus4 ,g1 ,i4 ,ceratozamia mexicana1 ,i1 microsporophyll with scars of sori 7s72 ,g1 sorus4 7,after ,thibout47 ,h4 ,stangeria paradoxa1 megastrobilus4 ,illustration3 ,fig4 #cic4 ,a4 ,stangeria paradoxa1 part of microstrobilus4 ,b1 ,d4 ,encephalartos villosus1 megastrobilus in surface-view and in section4 7 nat4 size47 ,c4 ,ceratozamia mexicana1 single megasporophyll4 ,illustration3 ,fig4 #cid4 ,macrozamia ,preissii1 megastrobilus and 7,a7 single megasporophyll2 a1 axis of cone2 p1 stalk of megasporophyll2 s1 unripe seeds4 7,after ,rendle47 ,illustration3 ,fig4 #cie4 ,zamia floridana4 ,ia1 complete plant2 a1 main trunk2 b1 branch-scar2 c1 secondary root2 d1 primary tap-root4 7 nat4 size47 ,ib1 ,ic1 megastrobilus4 7 nat4 size47 ,id1 megasporophyll4 7 nat4 size47 ,ie1 pinna4 7 nat4 size4 ,after ,wieland47 ,the microsporophylls 7figs4 #chi1 ,a2 #cib1 ,e7 are in all genera aggregated into strobili which often bear a close resemblance to seed-cones 7fig4 #cic1 ,a74 ,on a single sporophyll of ,cycas circinalis there may be as many as #gjj sporangia while in ,zamia floridana there are only two microsporangia4 ,the spore-output is large and in extreme cases1 e4g4 in ,dioon spinulosum1 the average number of spores in a sporangium is said to be #cj1jjjfa4 ,seeds4 ,in the great majority of recent species the seeds may be described as large and afford a striking contrast to the small seeds of the ,mesozoic ,bennettitales4 ,a feature of interest from the point of view of comparison with ,palaeozoic seeds is the absence of a resting stage1 germination in some cases following seed-fall without an interval4 ,as ,warming pointed out1 the embryo is often undeveloped when the seeds are shed4 ,an interesting fact is recorded by ,capt4 ,dorrien-,smith#fb with regard to seed-dispersal3 he describes the heavy pebble-like seeds of a ,macrozamia as being hurled from the ripe cones a distance of #ab ft4 ,the seeds of ,cycas are platyspermic2 the woody shell exposed on removal of the outer flesh is slightly flattened and has two prominent angles1 but three-angled seeds may occur as in ,ginkgo biloba 7fig4 #fca1 ,c74 ,in other genera the seeds are radiospermic4 ,the seed of ,encephalartos ,altensteinii#fc 7fig4 #cif1 ,d7 has a square-cut distal end with a small papilla at the summit of the unusually long micropylar canal 7#ag mm474 ,the stone of this seed 7fig4 #cif1 ,c7 shows parallel curved ridges which mark the position of vascular strands in the inner region of the outer flesh4 ,the large ovules of ,cycas circinalis#fd have an integument #a cm4 thick consisting of an outer and inner flesh and an intervening stony layer which reaches its greatest development at the base and apex4 ,three vascular strands enter the base of the seed1 the concentric strand breaks up in the broad inner flesh into a group of bundles which embrace but do not penetrate the lower end of the nucellus4 ,each of the two lateral strands branches in the outer flesh near its entrance into the seed2 the outer and larger collateral and mesarch bundle passes up close to the surface of the shell to the seed-apex1 while the inner branch penetrates the shell and1 occasionally branching1 passes up the inner region of the inner flesh as far as the micropyle4 ,in other seeds the tracheal supply of the outer flesh consists of several bundles and not two as in ,cycas4 ,the inner flesh abuts on the nucellus and is connected with it except at the apex 7fig4 #cif1 ,b74 ,in ripe seeds the nucellus is reduced to a thin membrane enclosing the large megaspore at the upper end of which is a depression 7fig4 #cif1 ,b7 or sometimes two depressions 7fig4 #cif1 ,i7 in the prothallus containing the archegonia4 ,in the seed of ,dioon edule#fe 7fig4 #cif1 ,a7 the position of the absciss-layer 7s7 is indicated by a slight transverse constriction4 ,in the seeds of ,bowenia1 constructed on the same plan1 the inner series of vascular strands appears to be nucellar in position1 thus differing from the strands in ,dioon1 ,cycas1 and other genera which are confined to the integument4 ,miss ,kershaw#ff in describing ,bowenia speaks of an upper and a lower pollen-chamber2 the former serves as a storage-place for the microspores prior to their further development in the lower chamber4 ,dr ,stopes#fg regards the integument as double in origin1 a view suggested by ,griffith#fh in #ahce1 and as homologous with the single integument plus the cupule of ,lagenostoma4 ,this view is supported by ,mrs ,thoday#fi3 on the other hand ,miss ,kershaw's investigation of ,bowenia seeds leads her to regard the integument as single4 ,although there would seem to be a prima facie case in favour of the dual nature of the integument1 the arguments on the other side have greater weight#gj4 ,illustration3 ,fig4 #cif4 ,illustration3 ,fig4 #cif4 ,a4 ,seed of ,dioon edule in longitudinal section2 a1 integument2 v1 vascular tissue2 m1 prothallus2 n1 nucellus2 p1 pollen-chamber2 s1 absciss-layer2 ar1 archegonia4 7,after ,chamberlain47 ,b1 ,b4 ,seed of ,cycas circinalis2 a1 v1 integument 7sarcotesta7 and vascular tissue2 b1 sclerotesta2 c1 inner sarcotesta2 m1 n1 prothallus and nucellus4 7,after ,stopes47 ,b4 ,apex of nucellus2 p1 pollen-chamber2 i1 integument2 n1 nucellus2 ch1 archegonial chamber2 ar1 archegonia4 ,c1 ,d4 ,seed of ,encephalartos ,altensteinii2 ,c1 surface of stone4 7,after ,stopes47 ,e4 ,stem of ,bowenia serrulata2 g1 level of ground4 7,after ,chamberlain47 ,f1 ,f4 ,pinnae of ,macrozamia heteromera4 ,g4 ,pollen-tube of ,microcycas ,calocoma4 7,after ,caldwell47 ,h4 ,transverse section of stem of ,encephalartos horridus2 s1 stele2 g1 girdle-bundles4 7,after ,mettenius47 ,i4 ,apical view of prothallus of ,cycas showing two archegonial chambers 7ch74 7,after ,treub47 ,k4 ,encephalartos ,barteri4 ,transverse section of stem2 x1 xylem2 p1 phloem4 7,after ,matte47 ,l4 ,cycas siamensis4 ,transverse section of vascular tissue of young stem4 7,after ,matte47 ,m4 ,cycas revoluta2 two motile sperms4 7,after ,miyake47 ,n4 ,long hair with short basal cell from the petiole of ,macrozamia heteromera4 7,after ,robertson47 ,o4 ,vascular bundle of ,dioon edule from base of petiole2 p1 phloem2 c1 cambium4 7,after ,mettenius47 ,recent observations point to the probability that insects play a part in the pollination of cycadean ovules4 ,kraus#ga drew attention to the strong smell emitted by the microstrobili of ,dioon edule and noticed that small bees were attracted to the ripe strobili of ,macrozamia1 while odourless cones of a neighbouring ,ceratozamia received no attention4 ,pearson#gb and ,rattray#gc have obtained evidence that beetles and weevils act as pollinators to species of ,encephalartos4 ,anatomical features4 ,allusion has already been made to some of the more striking anatomical features2 the large pith1 the occasional occurrence of medullary vascular bundles1 the presence of one or more cambiums1 the large size of the medullary rays1 etc4 ,it is worthy of remark that the occurrence of an anastomosing system of medullary bundles is not a constant feature within a genus2 in ,macrozamia ,fraseri such a system is present1 but absent in ,m4 ,denisoni#gd4 ,in the pith of stems with no medullary bundles cylinders of collateral bundles may occur in connexion with a fertile shoot4 ,these bundles arise from the inner face of the main cylinder and pass upwards as a domical system into the base of the terminal strobilus which is eventually pushed to one side by the growth of a lateral bud#ge4 ,the secondary xylem tracheids are usually provided with several rows of bordered pits on the radial walls and resemble those of the ,araucarieae#gf1 but in ,cycads the pits are often not contiguous and less compact in their distribution4 ,the wood of ,stangeria is peculiar in consisting of scalariform tracheids#gg 7fig4 #cig74 ,chamberlain describes growth-rings in the wood of ,dioon2 but this is exceptional4 ,in tangential sections of the stele leaf-trace bundles are constantly seen passing horizontally through the broad and deep medullary rays4 ,the pith-cast of a cycadean stem reproduced in fig4 #cih shows the wide meshes in the reticulum of tracheal tissue originally occupied by parenchyma1 which on decay left lenticular depressions represented on the cast by tapered convex areas occasionally bearing the impress of an outgoing trace in the form of a narrow groove4 ,the secondary phloem often rivals the xylem in breadth and is not always easily distinguishable from it2 it consists of sieve-tubes1 parenchyma1 and fibres4 ,the secondary cambial cylinders characteristic of ,cycas1 ,encephalartos1 ,macrozamia1 and ,bowenia1 to which reference was made in the summary of anatomical features1 arise in the pericycle1 and a few layers of pericyclic parenchyma occur between adjacent extrafascicular cylinders of xylem and phloem4 ,in a stem of ,cycas media #ce cm4 in diameter examined by ,worsdell there were #ab concentric cylinders4 ,matte#gh and ,miss ,dorety#gi have described partially flattened arcs of extrafascicular xylem and phloem in the hypocotyl of ,ceratozamia mexicana4 ,worsdell#hj first drew attention to the occasional occurrence of short tracheids on the inner edge of the secondary wood and to the spasmodic development of cambial arcs in the tissue between the extrafascicular cylinders forming strands of inversely orientated xylem and phloem4 ,more recent work by ,matte gives support to ,worsdell's comparison between ,medullosan stems and those of recent ,cycads with inversely orientated arcs or concentric vascular cylinders4 ,the ,french author draws attention to the close resemblance between the seedling stems of such species as ,encephalartos ,barteri 7fig4 #cif1 ,k7 and ,cycas siamensis 7fig4 #cif1 ,l7 with their polystelic type of structure and the adult stems of ,medullosa#ha4 ,in the stems of ,dioon1 ,microcycas1 ,stangeria1 and ,zamia no extrafascicular cylinders are recorded4 ,two main vascular bundles enter the cortex from each leaf-base and in most stems these diverge right and left and more or less completely encircle the stele before passing through the medullary rays and joining the inner portion of the xylem of the stele either as double or single bundles4 ,these girdle-bundles 7fig4 #cif1 ,h7 first described by ,karsten and ,mettenius form a very characteristic cycadean feature#hb4 ,adjacent girdles are joined by connecting cortical bundles and1 in addition1 there are cauline collateral bundles in the cortex which form an anastomosing system4 ,in some cases1 e4g4 species of ,macrozamia and occasionally in ,stangeria1 the female peduncle of a ,ceratozamia1 and in seedlings of ,bowenia and ,cycas revoluta#hc1 the leaf-traces pursue a direct course from petiole to stele as in stems of ,bennettitales4 ,it is noteworthy that in seedlings of ,microcycas#hd1 a genus characterised by a large number of male gametes--presumably a primitive feature--the leaf-traces are of the girdle-type4 ,the two bundles at the base of a petiole by repeated subdivision give rise to the numerous collateral strands of the rachis4 ,a leaf-trace in its passage to the leaf is like that of a ,conifer in having the protoxylem on its inner edge1 whereas in the petiole and elsewhere in the frond it is characterised by an arrangement of the xylem that has usually been described as mesarch4 ,a typical vascular bundle from a cycadean frond is seen in fig4 #cii1 ,c2 by far the greater part of the xylem is centripetal1 the centrifugal xylem being confined to an arc of scattered tracheids or a small strand separated by a few parenchymatous cells from the protoxylem4 ,illustration3 ,fig4 #cig4 ,tracheids from the stem of ,stangeria paradoxa4 7,after ,marsh47 ,illustration3 ,fig4 #cih4 ,pith-cast of a ,macrozamia stem1 7 nat4 size47 ,illustration3 ,fig4 #cii4 ,sketches illustrating the changes in the structure of ,cycadean vascular bundles in their course from stem to leaf3 cp1 cf1 centripetal and centrifugal xylem2 p1 phloem2 px1 protoxylem4 7,after ,marsh47 ,as considerable stress has been laid on the anatomical features of the cycadean foliar bundles in discussions on the affinities and phylogeny of certain ,palaeozoic genera1 it is important to consider the facts more closely#he4 ,french anatomists described the cycadean bundle as diploxylic on the ground that the centripetal and centrifugal xylems are distinctly different things1 the centripetal xylem being primary--a relic of a former organisation--and the centrifugal xylem secondary and homologous with the normal wood of the cauline bundle4 ,the term mesarch has in recent years been applied to the cycadean type of bundle4 ,a mesarch bundle is1 however1 one in which centripetal and centrifugal xylem are alike in origin1 both being primary structures derived from a desmogen strand4 ,typical mesarch bundles occur in several recent ferns2 in the stele of the ,osmundaceae1 ,gleichenia1 and other genera2 but in these plants the xylem is all produced directly from one primary desmogen region and there is no question of #8primary' and #8secondary' as in the two portions of the xylem of a cycadean bundle4 ,recent researches into the development of cycadean foliar bundles show that they do not conform to the mesarch type as generally understood4 ,a leaf-trace at the base of a petiole 7fig4 #cii1 ,a7 comprises centrifugal xylem only1 and this consists of regular rows of tracheids separated by medullary rays3 in the lower part of the petiole the structure is gradually modified1 the centrifugal xylem is reduced and the formation of centripetal xylem is initiated4 ,at a higher level 7fig4 #cii1 ,b7 the centripetal xylem is in excess of the centrifugal and the latter1 for a time connected with the former1 eventually becomes separated by a few parenchymatous cells from the protoxylem and persists as a small strand or arc of tracheids4 ,fig4 #cii illustrates stages in the transformation of a typical collateral bundle1 at the base of a ,stangeria petiole1 into one in which the xylem is almost wholly centripetal at a higher level in the axis of the frond4 ,a cambium is present in all3 in ,b the centrifugal xylem is more or less clearly differentiated into two portions1 loosely arranged tracheids near the phloem1 and the more compact groups abutting on the centripetal xylem3 figs4 ,c-,e show a further reduction in the centrifugal tracheids4 ,the conclusion drawn from developmental study is that the two xylem portions of the bundle are independent in origin#hf4 ,marsh has1 however1 shown that in ,stangeria bundles near the base of the petiole the centrifugal xylem consists of rows of secondary tracheids and an inner portion not in rows which connects the centrifugal with the centripetal elements2 this connecting portion1 he adds1 is #8probably primary and connects up the ,cycadean foliar bundle with the truly mesarch bundle of the ,cycadofilices4' ,illustration3 ,fig4 #djj4 ,cycas ,micholitzii4 ,vascular bundles in a forked pinna2 px1 protoxylem2 s1 sheath of thick-walled cells2 cf1 cp1 centrifugal and centripetal xylem4 ,in the xylem portion of the bundle from the midrib of a forked pinna of ,cycas ,micholitzii shown in fig4 #djj the centrifugal xylem elements are unusually numerous3 the space between the two xylems is occupied by parenchyma and the whole strand is enclosed by a sheath of crystal-containing cells1 s1 with thick inner walls4 ,fig4 #djj1 #a-d1 illustrates the gradual change in the form of the bundle in the region of dichotomy#hg4 ,the ground-tissue of the petiole is abundantly supplied with secretory canals and in the hypodermal region is a cylinder of stereome4 ,in some petioles1 e4g4 ,macrozamia heteromera#hh1 the ground-tissue cells are lignified and reticulately pitted1 a feature met with in some ,mesozoic cycadean leaves#hi4 ,in ,cycas media ,worsdell noticed a tendency of the leaf-trace bundles towards a concentric arrangement and similar vascular strands are recorded in the peduncle of ,dioon edule1 in various sporophylls#ij and in other cases4 ,it is possible1 as ,worsdell believes1 that the fairly frequent occurrence of concentric bundles in plants characterised by collateral bundles may have a phylogenetic significance4 ,the pinnae are dorsiventral and the veins exarch or pseudomesarch3 secretory canals occur between 7,encephalartos71 above1 or below the veins4 ,the mesophyll of ,cycas is characterised by the presence of isolated xylem-elements passing from the midrib to the edge of the lamina and1 as ,lignier#ia suggests1 these may be regarded as a reduced system of lateral conducting strands4 ,the epidermal cells of the leaflets have straight or slightly curved walls except in ,stangeria where they are undulate and fern-like#ib4 ,the stomata1 with few exceptions confined to the lower epidermis1 are larger than in other gymnosperms 7on the average #jge #jcd mm47 and are more or less depressed below the surface2 the guard-cells are usually surrounded by #d-f subsidiary cells4 ,the roots exhibit no feature to which attention need be called3 the pericycle is several cells broad and as in the stem there may be extrafascicular cylinders of xylem and phloem4 ,,chapter ,,xxix4 ,,pteridospermeae4 ,i4 ,,lyginopterideae4 ,,lyginopteris4 ,the genus ,lyginopteris is selected for the first place in this chapter simply on the ground that we have a fuller knowledge of its morphology than in the case of other types4 ,it is not regarded as the most primitive member of its class4 ,lyginopteris may be described in a few words as a plant having the habit and to a large extent the anatomical features of a ,fern1 but differing from existing ferns in the possession of integumented megasporangia or seeds and in the power of secondary growth in thickness by means of a cambium in both stem and root4 ,the seed 7,lagenostoma7 agrees with those of recent ,cycads and ,gnetales more closely than with the corresponding organs in ,conifers or any other group1 while the structure of the secondary wood is practically identical with that of ,cycads4 ,the microsporangia occur as groups of small bilocular sporangia1 or synangia1 at the tips of fertile pinnae of highly compound fronds4 ,nomenclature and ,historical ,summary4 ,in #ahff ,e4 ,w4 ,binney#ic of ,manchester published a short description of a small petrified stem from the ,lower ,coal ,measures of ,lancashire and named it ,dadoxylon oldhamium1 employing ,endlicher's term ,dadoxylon which that author substituted for ,pinites as previously used by ,witham#id4 ,three years later ,williamson#ie drew attention to certain features in which ,binney's type differs from the genus ,dadoxylon and substituted a new name ,dictyoxylon1 suggested by the reticulate pitting on the walls of the tracheids4 ,in a subsequent paper ,williamson#if gave a fuller description of ,binney's species and spoke of it as #8one of the most common plants in the calcareous nodules of the ,lower ,coal ,measures' of ,lancashire and ,yorkshire4 ,he connected certain casts of arborescent dimensions with ,binney's type on the ground that the surface-features of the casts are such as would be produced by partially decorticated stems having a hypodermal reticulum of mechanical tissue like that preserved in the small petrified specimen described by ,binney 7fig4 #djb74 ,mr ,carruthers called ,williamson's attention to a paper by ,mr ,gourlie#ig in which the generic name ,lyginodendron is instituted for stem-casts identical in surface-features with the fossils figured by ,williamson4 ,in spite of the much larger dimensions of the reticulum on the casts described by ,gourlie as compared with that in the outer cortex of ,binney's stem1 ,williamson concluded that ,lyginodendron is #8undoubtedly an inorganic cast of the prosenchymatous layer of the bark of ,dictyoxylon4' ,it is but fair to add that ,williamson was influenced in coming to this conclusion by a discovery by ,mr ,nield of a piece of a large petrified stem believed to be generically identical with ,binney's type1 but subsequently referred to a distinct genus#ih1 which was comparable in size with the stems responsible for ,gourlie's ,lyginodendron casts4 ,the type-specimen of ,gourlie's ,lyginodendron ,landsburgii#ii1 from ,carboniferous rocks at ,stevenston in ,ayrshire1 ,scotland1 is represented in fig4 #dja4 ,the convex areas represent casts of depressions in a reticulum of cortical tissue1 originally occupied by comparatively delicate cells1 which decayed or shrunk more quickly than the enclosing framework of stronger fibrous elements that remained as a prominent reticulum and produced the depressions bounding the raised portions of the cast4 ,such a cast would undoubtedly be formed by the stem on which ,binney founded his species3 the radially disposed bands of thick-walled cells seen in the outer part of the section 7fig4 #djb7 are portions of an irregular anastomosing mechanical system1 the reticulate arrangement of which is seen in the impression of a rachis of a ,lyginopteris frond shown in fig4 #dje1 ,e1 and indicated in the more slender axis reproduced in fig4 #djd1 ,a1 b4 ,this reticulate form of cortical stereome on which ,brongniart founded the genus ,dictyoxylon#ajj1 a term since applied by ,solms-,laubach and other authors to a certain type of cortex not confined to a single genus of plants1 occurs also in some ,palaeozoic lycopodiaceous stems#aja and in itself cannot be regarded as a safe criterion of botanical affinity4 ,the largest example of ,gourlie's ,lyginodendron that has come under my notice is an incomplete sandstone cast from ,upper ,carboniferous strata near ,harrogate reaching a length of #ajj cm4 and with convex areas #ac cm4 long4 ,a similar cast1 #cf cm4 broad1 has recently been figured by ,nathorst#ajb from the ,culm of ,spitzbergen1 and from the ,upper ,devonian of ,ellesmere ,land the same author has described impressions of a cortical reticulum under the name ,lyginodendron ,sverdrupi#ajc4 ,these specimens are interesting as pointing to the former occurrence in the ,arctic regions of stems--probably ,lepidodendroid--reaching the dimensions of a fairly large tree4 ,as ,potoni#ajd pointed out1 ,gourlie's generic name serves a useful purpose for casts of stems of the type shown in fig4 #dja that cannot be assigned to a definite systematic position4 ,the genus was first used for a specimen which has nothing to do with the plant usually spoken of as ,lyginodendron oldhamium 7,binney74 ,though loath to give up a name by which ,binney's type has long been known1 in spite of its retention in the second volume of this work ,i feel compelled so far to conform to the recognised principles governing nomenclature as to adopt ,potoni's generic term ,lyginopteris4 ,illustration3 ,fig4 #dja4 ,lyginodendron ,landsburgii4 7,kidston ,coll4 nat4 size47 ,lyginopteris oldhamia 7,binney74 i4 ,stem4 #ahff4 ,dadoxylon oldhamium1 ,binney1 ,proc4 ,lit4 ,phil4 ,manchester1 vol4 v4 p4 #aac4 #ahfi4 ,dictyoxylon oldhamium1 ,williamson1 ,monthly ,micros4 ,journ4 vol4 ii4 p4 #ff4 #ahgc4 ,lyginodendron oldhamium1 ,williamson1 ,phil4 ,trans4 ,roy4 ,soc4 vol4 clxiii4 p4 #djd4 #ahii4 ,lyginopteris oldhamia1 ,potoni1 ,lehrbuch der ,pflanzenpalaeontologie1 p4 #aga4 ii4 ,leaf4 #ahbh4 ,sphenopteris ,hoeninghausi1 ,brongniart1 ,prodrome1 p4 #ea4 #ahgb4 ,edraxylon1 ,williamson1 ,proc4 ,r4 ,soc4 vol4 xx4 p4 #dch4 #ahgd4 ,rachiopteris aspera1 ,williamson1 ,phil4 ,trans4 ,r4 ,soc4 vol4 clxiv4 p4 #fhd4 #ahgg4 ,calymmatotheca ,hoeninghausi1 ,stur1 ,culm ,flora1 ii4 p4 #bff4 #aije4 ,crossotheca ,hoeninghausi1 ,kidston1 ,proc4 ,r4 ,soc4 vol4 lxxvi4 p4 #ceh4 iii4 ,seed4 #ahgg4 ,lagenostoma1 ,williamson1 ,phil4 ,trans4 ,r4 ,soc4 vol4 clxvii4 p4 #bcd4 #aijc4 ,lagenostoma ,lomaxi1 ,oliver and ,scott1 ,proc4 ,r4 ,soc4 vol4 lxxi4 p4 #dgg4 iv4 ,root4 #ahgf4 ,kaloxylon ,hookeri1 ,williamson1 ,phil4 ,trans4 ,r4 ,soc4 vol4 clxvi4 p4 #bc4 ,illustration3 ,fig4 #djb4 ,lyginopteris oldhamia4 ,transverse section of the type-specimen in the ,binney ,collection1 ,sedgwick ,museum1 ,cambridge4 7,after ,arber47 i4 ,stem4 ,the petrified stem on which ,binney founded the species was first figured by ,dr ,arber#aje from a section in the ,binney collection in the ,sedgwick ,museum1 ,cambridge3 this section 7#ac mm4 in diameter7 is reproduced in fig4 #djb4 ,the most striking features are3 7i7 the pith consisting of an unusually large and irregular group of dark thick-walled parenchyma1 7ii7 the broad cylinder of manoxylic secondary xylem characterised by multiseriate medullary rays1 7iii7 the outer cortex composed of dark radially disposed and oblique bands of mechanical tissue separated from one another by partially destroyed and tangentially elongated parenchymatous elements4 ,it is this outer cortex that ,williamson aptly compared with the ,roman numerals on a clock-face4 ,in the perimedullary region and in contact with the inner edge of the secondary-xylem cylinder are six strands of primary xylem representing the xylem halves of collateral bundles separated from the primary phloem strands by the intervening cylinder of secondary wood4 ,two of the primary xylem strands in lateral contact are seen in fig4 #djd1 ,c2 the other four occur as separate bundles4 ,each primary xylem strand contains a small group of spirally thickened protoxylem elements 7px7 associated with a few parenchymatous cells4 ,the large primary tracheids internal to the protoxylem are characterised by multiseriate bordered pits on their walls1 while those external to the protoxylem1 which are in contact with the innermost secondary tracheids1 have scalariform pitting4 ,the dark patch s 7fig4 #djd1 ,c7 is a portion of the large group of sclerenchymatous cells1 shown in figs4 #djb1 #djc4 ,the perimedullary xylem strands of mesarch structure are the lower portions of leaf-traces and1 as ,scott points out1 #8each of the bundles surrounding the pith is1 in fact1 a sympodium1 composed of the united lower ends of successive adjacent leaf-traces4' ,the larger of the two bundles shown in fig4 #djd1 ,c1 is on the point of passing out to a leaf1 while the smaller strand is on its way to a higher level before bending outwards through the secondary wood4 ,slightly beyond the middle of the secondary xylem there is an arc of narrower tracheids comparable with an incomplete annual ring4 ,although zones or arcs of narrow tracheids are not uncommon in the wood of ,lyginopteris there is no satisfactory evidence of regularly recurring seasonal changes4 ,on the outer face of the secondary wood are a few leaf-trace strands pursuing a vertical course in the pericycle region2 but the structure and behaviour of these bundles are more clearly illustrated in the stem reproduced in fig4 #djc4 ,the tissue between the crushed phloem and pericycle and the outer cortex 7fig4 #djb7 consists of radially compressed parenchyma with scattered secretory cells separated from the more internal tissue by a narrow band of periderm formed by a phellogen in the outer part of the pericycle4 ,a larger and better preserved stem1 #cg cm4 in diameter1 is seen in fig4 #djc4 ,in this stem the pith of parenchyma and scattered sclerenchymatous nests is larger in proportion to the stele than in ,binney's type-specimen4 ,from the inner edge of the secondary xylem several primary xylem-strands project as rounded wedges or tangentially elongated groups where two traces are laterally united in the perimedullary zone4 ,the cylinder of secondary wood is partially interrupted at r by the bending outwards of the stele of an adventitious root cut across transversely as it bends down after emerging from the outer cortical region4 ,in more or less close association with the outer surface of the secondary xylem are four pairs of leaf-trace bundles and one larger trace at d containing two widely separated protoxylem strands and faced externally with an arc of secondary xylem3 this is a leaf-trace which shows by the slight constriction on the outer edge of its primary xylem that it is beginning to divide into a pair of equal strands4 ,a precisely similar strand is shown on a larger scale in fig4 #djd1 ,d4 ,the twin bundles seen at b1 fig4 #djc1 represent a divided leaf-trace at a slightly higher level than the partially severed trace at d1 and the arcs of secondary xylem are narrower4 ,the appearance of the double leaf-trace at a still higher level is shown at c3 the two strands are farther apart and the secondary xylem has almost disappeared1 while those at e1 nearer their entrance into the leaf-stalk1 consist exclusively of primary xylem and phloem4 ,at a the two strands of a leaf-trace1 still nearer to the petiole1 are inclined towards one another preparatory to reunion after reaching the leaf-stalk4 ,a slender root is seen in transverse section at r immediately outside the two leaf-bundles4 ,as ,williamson and ,scott#ajf have pointed out1 there are always five leaf-traces beyond the xylem cylinder of a ,lyginopteris stem as seen in transverse section1 and these traces in the pericycle1 separated from one another by of the circumference1 alternate in position with the lower portions of leaf-traces in the perimedullary region of the same stem4 ,the phyllotaxis is thus seen to be 4 ,illustration3 ,fig4 #djc4 ,lyginopteris oldhamia4 a-e1 foliar bundles2 f1 decurrent base of petiole2 r1 r1 roots2 s1 seed 7,lagenostoma74 7 #c4 ,kidston ,coll4 #eib1 ,b47 ,the secondary wood is succeeded by a cambium of normal structure passing gradually into a narrow band of secondary phloem which in well-preserved stems is seen to consist of sieve-tubes and parenchyma with medullary rays rather broader than those in the xylem4 ,beyond the phloem is the comparatively broad pericycle consisting of parenchyma with nests of sclerenchyma like those in the pith and scattered secretory cells4 ,in the outer layers of the pericycle a phellogen was formed at an early stage in the growth of the plant1 producing several layers of secondary tissue1 which is regarded as periderm and forms a conspicuous feature in ,lyginopteris stems2 it appears as a comparatively dark sinuous band where it bends outwards to wrap round the leaf-traces in their almost vertical course through the pericyclic region 7fig4 #djc74 ,the periderm is clearly seen at p close to the crushed secondary phloem of the dividing leaf-trace in fig4 #djd1 ,d4 ,all the leaf-traces seen in fig4 #djc beyond the secondary wood are still within the deep-seated periderm and1 as ,williamson and ,scott showed1 each leaf-trace after emerging from the secondary wood remains in the pericycle-zone for a length of five internodes as it very gradually inclines outwards4 ,once free from this region the twin bundles bend more sharply towards the petiole4 ,stated briefly1 the history of each leaf-trace from the perimedullary region to the leaf-base is as follows3 at the outer edge of the pith a single trace consists of a mesarch xylem bundle with one protoxylem strand2 it passes vertically through five internodes and then bends out through a foliar gap in the xylem-cylinder1 and the primary tracheids receive additions from the cambium of the stele on their outer face4 ,as the trace leaves the secondary xylem it bends upwards and1 as seen at d1 fig4 #djc1 begins to divide into twin bundles4 ,as the trace passes higher the bisection of the protoxylem and metaxylem is completed and the secondary xylem-arcs are gradually lost until the separate strands of each pair are reduced to single mesarch bundles composed wholly of primary tracheids4 ,as the trace bends outwards through the cortex the phloem gradually encircles each xylem-strand until a concentric structure is substituted for the collateral disposition of the conducting tissue4 ,at the same time the protoxylem strands divide and occupy a position near the inner edge of the metaxylem4 ,on reaching the petiole or after passing some distance up the axis of the frond1 the twin bundles unite and usually form a ,v-shaped vascular strand 7figs4 #djd1 ,e2 #dje1 ,a74 ,the single meristele subsequently divides into two equal portions preparatory to the bifurcation of the petiole 7fig4 #djf74 ,the inner cortex1 consisting of parenchymatous tissue and many secretory cells with an occasional group of sclerenchymatous elements in place of the abundant nests of this tissue in the pericycle1 has been invaded in the stem shown in fig4 #djc by numerous rootlets of ,stigmaria and ,lyginopteris1 some of which are seen interrupting the continuity of the outer cortex4 ,the greater width of the cortical region at f1 fig4 #djc1 is due to the decurrent base of a petiole the meristele of which is not included in the section4 ,the lighter and broader bands between the cross-sections of the stereome-network in the outer cortex are occupied by remains of tangentially stretched parenchymatous cells1 and beyond this zone in a younger stem there are a few layers of parenchyma forming the superficial tissue1 but there appears to be no well-defined epidermal layer4 ,illustration3 ,fig4 #djd4 ,lyginopteris oldhamia4 ,a1 ,b4 ,frond fragments2 a1 pinnule2 b1 reticulum of sclerenchyma4 ,c4 ,portion of stele of the stem reproduced in fig4 #djb4 ,d4 px1 protoxylem2 s1 sclerenchyma2 leaf-trace close to the edge of the secondary xylem2 p1 periderm4 ,e4 ,petiole2 m1 meristele4 7,a1 ,kidston ,coll4 #ffd ,b2 ,b1 ,camb4 ,botany ,school #ejh2 ,c1 ,binney ,coll4 #agi2 ,d1 ,e1 ,camb4 ,botany ,school1 #ic1 #aei47 ,young stems have been recognised in which there is very little secondary xylem and phloem3 in these the stereome bands in the outer cortex are closer together than in the stretched hypodermal tissue of older shoots and the scattered sclerous nests are represented by unthickened cells4 ,in addition to young stems ,williamson and ,scott described a distinct type of small stem in which the primary xylem forms an almost complete ring#ajg comparable with the primary xylem of some adult ,sigillarian stems 7vol4 ii4 p4 #bbj7 but distinguished by its mesarch structure and by the reticulate pitting of the centripetal xylem4 ,a characteristic feature of the stem is the occurrence of emergences from the outer cortex which have the structure either of spinous processes1 broadly linear or flask-shaped1 or of stalked glands#ajh4 ,a portion of a glandular emergence is shown in fig4 #dje1 ,b3 the group of small cells immediately below the blunt apex is in this instance still intact though showing signs of disorganisation in the centre2 but in many cases the secretory tissue has not been preserved and the head of the emergence is occupied by a space4 ,a single stoma is seen at s in longitudinal section4 ,further reference to the emergences is made in the description of the leaf4 ,it occasionally happens that a meristematic layer is formed in the parenchymatous tissue immediately internal to some of the perimedullary xylem strands of a ,lyginopteris stem from which either secondary parenchyma is produced or a zone of secondary xylem and phloem1 the phloem facing the centre of the pith4 ,an example of such internal xylem was figured by ,williamson#aji and similar occurrences are more fully dealt with by ,williamson and ,scott#aaj who consider that the perimedullary cambium may represent an internal extension through a leaf-gap of the normal cambial cylinder4 ,in the stem represented in fig4 #djc there are two perimedullary xylem strands to the left of the bottom of the ,v-shaped gap in the secondary xylem-cylinder1 r1 and on the inner face of one of these1 as shown in fig4 #dje1 ,c1 there is a narrow arc of internal secondary xylem1 c1 between the xylem-strand and the outer edge of one of the sclerous nests4 ,the sporadic occurrence of arcs of inversely orientated secondary vascular tissue affords an interesting parallel with a similar morphological feature in some recent ,dicotyledonous genera such as ,tecoma and ,iodes4 ,as ,williamson and ,scott point out1 this similarity affords #8a striking warning against the indiscriminate use of even conspicuous anatomical characters#aaa4' ,while admitting the necessity of guarding against the danger of attaching importance to occasional and abnormal characters they may have some significance as collateral evidence in comparisons of different types of stems4 ,it is conceivable that these anomalous arcs of secondary tissue on the inner side of the primary xylem strands may1 as ,worsdell#aab maintains1 be reversions to an ancestral character and in this sense comparable with the strands of inverted vascular tissue in some recent ,cycadean stems4 ,the question of relationship of ,lyginopteris and allied types to recent ,cycads and the ,palaeozoic ,medulloseae is considered in a later chapter4 ,in #aijb ,lomax#aac described two branching specimens of ,lyginopteris1 and more recently two others have been discovered at a locality near ,bacup in ,lancashire which have been thoroughly investigated by ,miss ,brenchley#aad who constructed models from drawings of serial sections#aae4 ,one specimen shows six leaf-bases in a length of #d inches and branches spring from the axils of five of them3 some of the branches show secondary ramifications4 ,the phyllotaxis of the leaf-bases on a branch is always the reverse of that on the main stem1 a divergence to which no parallel was found in a selection of trees and shrubs examined by ,miss ,brenchley4 ,the secondary wood of the stem swells below the point of exit of a branch and frequently a fairly large amount of wood occurs in the pith when a branch is given off3 this anomalous wood may help to close the branch-gap4 ii4 ,leaf4 ,in his account of ,lyginopteris stems published in #ahgc ,williamson#aaf suggested that the vascular bundles met with outside the xylem-cylinder might be the leaf-traces of large fronds and expressed the opinion that the #8stems or petioles' previously described by him under the generic name ,edraxylon might belong to ,lyginopteris4 ,a year later he substituted the name ,rachiopteris aspera for the petioles previously referred to ,edraxylon and inclined to the view that this type of ,rachiopteris may be the petiole of the ,carboniferous fronds known as ,sphenopteris ,hoeninghausi ,brongn41 an inference based to a large extent on the occurrence of emergences on ,rachiopteris aspera 7fig4 #djd1 ,e7 preserved as petrifactions like those on impressions of ,sphenopteris ,hoeninghausi as figured by ,brongniart 7figs4 #djd1 ,a2 #dje1 ,d1 ,d'74 ,in #ahij ,williamson was able to demonstrate the truth of the surmise that ,rachiopteris aspera and ,lyginopteris oldhamia are respectively the petiole and stem of the same plant1 which he believed to be an arborescent fern#aag4 ,the petioles of ,lyginopteris fronds1 which may reach a diameter of #a cm41 are attached by a broad base to the stem1 and as already suggested by the number of internodes traversed by each leaf-trace1 the leaves are comparatively far apart4 ,a transverse section of a petiole is shown diagrammatically in fig4 #dje ,a4 ,the hypodermal stereome is a prominent feature1 but the narrow radial plates of the stem-cortex tend to be replaced in the rachis by broader and confluent masses of strengthening elements3 the upper surface of the petiole is slightly grooved4 ,glandular and spinous emergences are often very abundant1 as in the section reproduced in fig4 #djd1 ,e4 ,a glandular emergence is seen at a in fig4 #dje1 ,a4 ,the spinous emergences may be compared with those of ,davallia 7,odontosoria7 aculeata#aah1 a ,west ,indian fern of climbing habit and with the prickles on ,hemitelia and other recent ,cyatheaceous fronds#aai1 while capitate glands1 though simpler than those of ,lyginopteris1 occur on the leaf-stalks of some recent ,polypodiaceous species#abj4 ,the concentric meristele may consist in the lower part of the petiole of two separate and slightly curved strands like those seen in fig4 #djd1 ,e1 m3 sooner or later the two strands unite to form a wide-open ,v or a ,w-shaped bundle with several slightly internal protoxylem groups close to the lower edge4 ,the two sections represented in fig4 #djf1 ,a and ,b show the gradual divergence of the two meristeles of a petiole as they approach the level where it divides into two equal branches1 a characteristic feature of ,sphenopteris ,hoeninghausi and allied fronds4 ,at a lower level than that represented in fig4 #djf the vascular strand of the petiole would have the form of a ,w as figured by ,williamson in one of his earlier memoirs#aba4 ,the phloem with scattered secretory sacs and the adjacent tissue of the leaf-stalk are occasionally preserved in wonderful perfection#abb4 ,no endodermis has been recognised4 ,sclerous nests are scattered in the ground-tissue as are also secretory sacs 7figs4 #djd1 ,e2 #dje1 ,a74 ,a small root r has penetrated the parenchyma of the rachis shown in fig4 #dje1 ,a4 ,illustration3 ,fig4 #dje4 ,lyginopteris oldhamia4 ,a1 petiole section2 a1 glandular emergence2 r1 root4 ,b1 stalked gland2 s1 stoma4 ,c1 inner edge of wood of a stem2 c1 arc of inversely orientated vascular tissue4 ,d1 ,d'1 part of a frond of ,sphenopteris ,hoeninghausi4 ,e1 part of axis of ,d4 7,a1 ,c1 ,d1 ,kidston ,coll42 ,b1 ,manchester ,coll4 ,r4 #fde47 ,illustration3 ,fig4 #djf4 ,lyginopteris oldhamia4 ,transverse section illustrating branching of petiole4 #e4 7,from a drawing supplied by ,prof4 ,oliver47 ,sphenopteris ,hoeninghausi ,brongn4#abc1 founded on material from ,english ,coal ,measures1 was regarded by ,williamson as the foliage of ,lyginopteris chiefly on the ground of the occurrence of emergences on the axes 7figs4 #djd1 ,a1 ,b7 and laminae of the impressions like those on the petrified stems1 and this comparison received support from the resemblance of the fragments of pinnules associated with ,lyginopteris and its petioles in the calcareous nodules to the leaflets of ,brongniart's type4 ,this identification is supported by subsequent work4 ,the quadripinnate fronds1 which attain a considerable size1 resemble those of recent species of ,davallia and other ferns1 but the forking of the rachis and branches of the frond is a striking feature3 the pinnae may reach a length of #ae cm4#abd ,the portion of carbonised rachis shown in fig4 #dje1 ,e1 reveals the existence of a hypodermal reticulum like that in the outer cortex of a ,lyginopteris stem and the same feature is seen in the more slender axis represented in fig4 #djd1 ,a1 at b4#abe ,the pinnules are usually deeply lobed and the segments may be comparatively broad and blunt or narrow#abf 7fig4 #bij1 ,c1 vol4 ii4 p4 #cii2 fig4 #djd1 ,a1 a1 ,b2 fig4 #dje1 ,d'74 ,the lamina has a well marked dorsiventral structure3 the palisade-tissue next the upper surface is separated from the epidermis by small hypodermal cells1 possibly functioning as a water-storage layer1 and the central part of the mesophyll consists of loose aerenchyma3 the veins are collateral as in recent ferns and stomata occur in the lower epidermis4 ,emergences are seen both on impressions 7fig4 #dje1 ,d'7 and on petrified specimens4 ,a striking feature of the pinnules is the rounded surface caused by the revolute edge of the lamina as seen in the section reproduced in fig4 #djd1 ,b4 ,this character coupled with the occasional occurrence of groups of short tracheal elements at the termination of the veins denotes a tendency to a xerophilous habit4 ,on the strength of a very close resemblance between ,sphenopteris ,hoeninghausi and ,calymmatotheca ,stangeri 7fig4 #djh1 ,e1 ,f7--characterised by fertile pinnules bearing stellate groups of small linear valves1 regarded by ,stur as the open lobes of an indusium--,zeiller included ,brongniart's type in the genus ,calymmatotheca4 ,the resemblance in general habit between the two species extends to the presence in their rachises of the ,dictyoxylon form of cortex#abg4 ,the view formerly held by some authors that the valve-like appendages to the fertile segments of ,calymmatotheca are sporangia is incorrect3 a re-examination of ,stur's specimen 7fig4 #djh1 ,e1 ,f7 has confirmed the original description#abh4 ,the stellate lobes are now regarded as portions of a cupular investment of a seed similar to ,lagenostoma ,lomaxi1 the female reproductive apparatus of ,lyginopteris oldhamia4 ,the axes of the fertile pinnae bear small thorn-like emergences probably identical with those on the cupule of ,lagenostoma and on the petioles of ,lyginopteris oldhamia4 ,it was stated in vol4 ii that the fronds known as ,sphenopteris ,linkii 7,goepp47 represent1 with other closely allied forms1 leaves belonging to ,heterangium stems4 ,this statement was based on a misconception3 the rachis of ,sphenopteris ,linkii1 as ,i have satisfied myself by an examination of impressions shown to me by ,dr ,kidston1 exhibits the reticulate pattern characteristic of ,lyginopteris and not the transverse ribs characteristic of ,heterangium4 ,it is not an easy task even for those most familiar with ,carboniferous fronds to distinguish clearly between species agreeing generally with ,sphenopteris ,hoeninghausi1 a species regarded by some authors as the type of a group of very similar and closely allied forms all of which were probably borne on stems referable to the genus ,lyginopteris4 ,the species ,lyginopteris oldhamia as generally understood probably includes more than one specific type1 and it is safe to assert that in the ,carboniferous period ,lyginopteris was represented by several forms characterised by highly compound fronds with forked rachises like ,sphenopteris ,linkii1 ,s4 ,hoeninghausi1 and others4 ,the features characteristic of fronds included in the ,sphenopteris ,hoeninghausi group have recently been described by ,gothan#abi4 ,stur's generic name ,calymmatotheca originally applied to the species ,c4 ,stangeri was applied to ,sphenopteris ,hoeninghausi by ,zeiller1 and although the fronds of the latter type have not been found with fertile appendages of the ,calymmatotheca type there can be no doubt as to the generic identity of these1 barely distinguishable1 species both of which belong to stems of ,lyginopteris4 ,prof4 ,johnson#acj has recently described some impressions from the ,coal ,measures of ,ireland1 which he refers to ,s4 ,hoeninghausi1 bearing stellate groups of lobes like those of ,calymmatotheca1 and in one case he describes a seed in the middle of the carbonised remains of a stellate group of cupular segments4 ,an examination of the specimen in ,dublin convinced me that there is no satisfactory evidence of the seed-nature of the appearance on the rock believed by ,johnson to be an elliptical ,lagenostoma-like seed4 ,the actual attachment of the stellate lobes to the pinnae of the frond is not clearly demonstrated4 iii4 ,microsporangia4 ,in #aije ,kidston#aca announced the discovery of microsporangia on fronds of ,lyginopteris3 he described specimens from the ,coal ,measures of ,dudley identified by him with ,sphenopteris ,hoeninghausi showing sterile and fertile pinnae in organic connexion4 ,the fertile pinnules 7fig4 #djg1 ,b7 are slightly expanded distally into an oval limb about #b mm4 long bearing #f to #g bilocular fusiform microsporangia #c mm4 long and #ae mm4 broad3 in the immature condition the sorus is hemispherical1 the summit being formed of the incurved apices of the sporangia4 ,at maturity the sporangia spread out1 the sorus assuming the form of an epaulet4 ,fig4 #djh1 ,h1 shows a sorus in transverse section and in fig4 #djh1 ,g1 the limb and two pendulous sporangia are shown4 ,the microspores1 #ej-gj in diameter1 are studded with numerous blunt spines and each spore shows a triradiate ridge4 ,the section reproduced in fig4 #djg1 ,a1 from the ,coal ,measures of ,oldham is probably a bilocular sporangium of the same type as those described by ,kidston from ,dudley4 ,dr ,kidston#acb describes a second type of microsporangial sorus as ,crossotheca ,hughesiana which agrees closely with ,c4 ,hoeninghausi1 but the fertile segments are not associated with any sterile pinnae4 ,the generic name ,crossotheca1 founded by ,zeiller#acc in #ahhc1 was substituted for ,sphenopteris on the ground that ,brongniart's species ,s4 ,hoeninghausi is shown to possess sporangia of the ,crossotheca type4 ,if ,kidston's specific determination is correct1 his discovery demonstrates that ,lyginopteris fronds bore microsporangia having the characters of ,crossotheca1 a type characteristic of several ,carboniferous species belonging both to the form-genera ,sphenopteris and ,pecopteris4 ,reference has already been made to the difficulty of distinguishing between impressions of fronds of the ,sphenopteris ,hoeninghausi group1 a difficulty that is illustrated by ,dr ,gothan's statement#acd that the ,dudley specimens of ,crossotheca are not identical in the character of the sterile pinnules with ,sphenopteris ,hoeninghausi4 ,an examination of ,dr ,kidston's specimens led me to agree with his determination2 but1 it may be asked1 have we any evidence of the association with ,lyginopteris fronds of sporangia other than those of the ,crossotheca type8 ,prof4 ,chodat#ace believes that certain petrified fragments of pinnules occasionally met with in the calcareous nodules bearing sessile and apparently annulate sporangia belong to ,lyginopteris fronds4 ,these sporangia appear to be identical with those named by ,scott ,pteridotheca ,butterworthi#acf and regarded by him as filicean sporangia that cannot be referred to any known ,carboniferous genus4 ,the piece of lamina bearing an empty sporangium1 which may or may not have possessed an annulus1 reproduced in fig4 #djg1 ,c1 occurs in association with the larger specimen shown in fig4 #djd1 ,b1 and it would seem not unreasonable to regard both as parts of the same frond1 namely a frond of ,lyginopteris4 ,as ,prof4 ,weiss#acg points out1 the accurate determination of small pieces of petrified pinnules is exceedingly difficult and without more decisive evidence we are hardly justified in asserting that the sporangia figured by ,chodat and ,scott and that shown in fig4 #djg belong to the genus ,lyginopteris4 ,although the available data appear to favour the view generally held that ,kidston's conclusion is correct additional evidence would be welcome4 ,illustration3 ,fig4 #djg4 ,a1 ,b4 ,crossotheca ,hoeninghausi4 ,c4 ,pinnule with a sporangium1 s4 7,a1 ,kidston ,coll4 #abgg2 ,b1 after ,kidston2 ,c1 ,camb4 ,botany ,school1 #ejh47 ,telangium4 ,reference was made in vol4 ii4#ach to the genus ,telangium instituted by ,dr ,benson for some petrified sporangia from the ,coal ,measures regarded by her as the microsporangia of a ,pteridosperm1 probably ,lyginopteris4 ,the sporangia of ,telangium are similar to those of ,crossotheca4 ,scott points out that they are borne on a flat disc or lamina #8quite comparable to a fertile pinna of ,crossotheca#aci1' and he concludes that these sporangia are not generically distinct from the impressions on which the genus ,crossotheca was founded4 ,kidston#adj regards ,telangium ,scotti1 ,benson1 as the microsporangium of a ,pteridosperm though not of ,lyginopteris1 on the ground that the microsporangia described by ,miss ,benson are not attached to a limb and that they have a single loculus in place of the double loculus 7fig4 #djg1 ,a7 of ,crossotheca4 ,the presence of a limb in ,telangium recognised by ,scott removes one of these distinguishing features4 ,there are1 however1 no adequate reasons for regarding ,telangium ,scotti as specifically identical with ,crossotheca ,hoeninghausi4 ,the synangium of ,telangium ,scotti1 #e mm4 in length1 consists of #f-ab sporangia united basally and opening when ripe by longitudinal dehiscence4 ,fig4 #dic1 ,e1 shows eight sporangia of a synangium in transverse section3 the two sporangia at the lower end of the section are less distinct than the others1 some are full of spores and others have shed their contents by the splitting of the thin inner walls of the loculi4 ,the sporangial walls are composed of an outer layer of large cells with dark contents succeeded by #b-c layers of smaller and crushed cells4 ,the spores1 #e-f #ce-d in diameter1 have a reticulately sculptured exine3 ,dr ,benson#ada states that they agree closely with pollen-grains found in the pollen-chamber of ,lagenostoma ovoides except in their slightly smaller size2 she notes the association of ,telangium with fragments of the vegetative organs of ,lyginopteris and draws attention to resemblances in the structure of the tissues2 but the most interesting comparison1 at least in an academic sense1 is with the seed ,lagenostoma1 the integumented megasporangium of ,lyginopteris4 ,dr ,benson points out that a transverse section of a ,lagenostoma in the plane of the canopy1 showing the nucellar apex surrounded by radially disposed chambers 7fig4 #dji71 presents a certain resemblance to a synangium of ,telangium ,scotti2 and it is suggested that the chambers encircling the nucellus may represent sterilised sister-sporangia#adb4 #8,the seed in fact is assumed to be a synangium in which all but one of the sporangia are sterile1 and form an integument to the one fertile sporangium which has become a megasporangium with one large megaspore4' ,this view1 though clearly incapable of confirmation in the present state of our knowledge1 is not merely an ingenious hypothesis but a stimulating suggestion as to possible homologies3 as an argument in favour of associating ,lagenostoma and ,telangium as the spore-bearing organs of the same plant it has but little weight4 iv4 ,the ,seed4 ,lagenostoma ,williamson4 ,lagenostoma ,lomaxi1 ,oliver and ,scott ex ,williamson1 ,,ms4 ,in #ahgg ,williamson#adc proposed the generic name ,lagenostoma for some petrified seeds from the ,lower ,coal ,measures of ,lancashire and described two species1 ,lagenostoma ovoides and ,l4 physoides3 in his ,,ms4 ,catalogue a third type is referred to as ,lagenostoma ,lomaxi4 ,it is this third type that ,prof4 ,oliver was the first to recognise as the megaspore-bearing organ of ,lyginopteris oldhamia4 ,its structure has been thoroughly described by ,oliver and ,scott#add and these authors contribute a judicial summary of the evidence on which ,lagenostoma and ,lyginopteris are believed to stand for one and the same plant4 ,the evidence is based chiefly on the following considerations3 an agreement in the structure of the vascular bundles in the investments of the seed with those in the leaves of ,lyginopteris2 the presence in the outer envelope of the seed of stalked glands identical with those on the stems and petioles4 ,the evidence does not as yet amount to absolute proof1 as the seeds1 which occur either with or without a stalk1 have not been found attached to a ,lyginopteris frond4 ,but #8where vegetative and reproductive organs presenting identical structural features1 not known to occur in other plants1 are thus found in close and constant association1 the inference that the one belonged to the other appears irresistible4' ,while most botanists believe that a satisfactory case is established there are a few#ade who refuse to believe in a connexion between ,lagenostoma and ,lyginopteris until an actual union has been demonstrated4 ,the discovery by ,kidston#adf of seeds attached to pinnae bearing ,neuropteris pinnules and the demonstration of organic continuity between seeds and the pinnules of other ,palaeozoic fern-like fronds supply abundant confirmatory evidence that leaves no doubt as to the occurrence of seeds on modified pinnae of ,sphenopteris ,hoeninghausi and of other closely allied fronds which represent the foliage of different forms of ,lyginopteris4 ,in this connexion it is pertinent to add that ,grand',eury#adg has found seeds of the ,lagenostoma type in close association with impressions of ,sphenopteris ,dubuissonis and other leaves of similar habit4 ,a seed of ,lagenostoma ,lomaxi reaches a length of #ee mm4 with a maximum diameter of #dd mm42 it is broadly oval or barrel-like 7fig4 #djh1 ,c7 and when immature was invested by a loose irregularly lobed glandular envelope 7fig4 #djh1 ,b7 from which the seed eventually freed itself by a natural process of abscission4 ,the central body or nucellus1 except in the apical region1 is concrescent with a fairly stout integument or testa 7fig4 #djh1 ,c1 f7 the outer portion of which is characterised by regular longitudinal rows of palisade-like cells comparable with the broad palisade-layer in the sporocarp of ,pilularia4 ,on the exposed surface of this palisade-tissue are small dark structureless pegs#adh1 possibly the remains of a mucilaginous layer such as occurs on the seed-coats of some recent ,flowering plants4 ,at the base of the nucellus the chalazal region1 fig4 #djh1 ,c1 ch1 is provided with sclerous elements and forms a hard investment to the axial vascular strand from the pedicel4 ,it is at the base of this chalazal region that the seed is eventually cut off by an absciss-layer4 ,the integument is supplied throughout its length by nine vascular bundles of endarch1 or approximately endarch1 structure4 ,the free portion of the integument seen from the outside 7fig4 #djh1 ,b7 has the form of a fluted cone with a circular opening at its summit4 ,the greater part of this domical apex1 as seen in longitudinal section in fig4 #djh1 ,c1 appears to be hollow1 but in the living state the dome1 or canopy as ,williamson called it1 was filled with parenchyma in which the vascular bundles were embedded and1 as shown in the transverse section in fig4 #dji1 the canopy is divided into compartments by radial septa which in its basal region are replaced by regular and deep furrows on the inner face4 ,enclosed by the canopy1 with its outer surface fluted as the result of the partial collapse of the outer wall of each compartment due to the decay of the filling tissue1 is the flask-shaped apex of the nucellus2 between the apical cone of nucellar parenchyma and the superficial layer is an annular cavity which ,williamson#adi called the lagenostome4 ,the parenchymatous core tapers to a narrow summit which slightly overtops the integument and is constricted at the broad base 7fig4 #dic1 ,a1 ,b2 page #caa74 ,the bottle-shaped apical tissue is separated by an annular space1 c1 fig4 #dic1 ,b1 from the limiting layer of the nucellus3 this space is the pollen-chamber formed in the living seed by the disorganisation of the subepidermal cells of the nucellar apex4 ,the pollen-chamber is a feature characteristic of recent cycadean ovules 7see p4 #f74 ,in ,lagenostoma the annular form of the pollen-chamber is a peculiarity distinguishing this type of seed from those of recent ,gymnosperms and most other ,palaeozoic seeds4 ,as ,oliver says1 it marks an #8advance in precision'#aej over other forms as the microspores which fall into the chamber are brought direct to the surface of the underlying megaspore and presumably to the archegonia which1 it is reasonable to believe1 were disposed in a circle at the base of the annular crevice4 ,microspores frequently occur in the pollen-chamber and some have been discovered apparently in the act of liberating male gametes#aea4 ,illustration3 ,fig4 #djh4 ,a1 ,a1 ,lagenospermum ,sinclairi4 ,b1 ,lagenostoma1 restoration4 ,c1 ,lagenostoma ,lomaxi2 c1 micropyle2 d1 space between integument and nucellus2 e1 cupule2 f1 integument2 ch1 chalaza4 ,d1 microspores of ,lagenostoma ovoides4 ,e1 ,f1 ,calymmatotheca ,stangeri4 ,g1 ,h1 ,crossotheca ,hoeninghausi4 ,h1 section of ,g in line of arrow4 7,a1 after ,arber2 ,b1 ,c1 ,e1 ,f1 after ,oliver2 ,d1 after ,benson2 ,g1 ,h1 after ,kidston47 ,illustration3 ,fig4 #dji4 ,lagenostoma4 ,transverse section near the micropyle1 showing the pollen-chamber1 pc1 the space1 s1 between the nucellus and integument1 the fluted canopy with vascular bundles1 v4 7,after ,oliver47 ,the outer wall of the nucellus is bounded externally by a similar circular space 7d1 figs4 #djh1 ,c2 #dic1 ,b7 which separates it from the domical canopy4 ,in the great majority of specimens the central tissue of the seed is not preserved and an empty sac supported from the base of the nucellus-apex occupies nearly the whole of the interior3 the shrunken wall of the sac is all that remains of the large megaspore4 ,it would seem1 then1 that the nucellus was almost completely destroyed as a consequence of the growth of the megaspore or embryo-sac1 which eventually occupied nearly the whole of the seed-body4 ,in an exceptionally well preserved specimen recently described and admirably illustrated by ,mr ,mc,lean#aeb part of the parenchymatous tissue of the prothallus which originally filled the megaspore is clearly seen3 its surface-layer consists of small cells succeeded by a broad band of radially elongated elements closely resembling the alveoli in the prothalli of some recent ,gymnosperms1 particularly certain ,conifers4 ,no archegonia have been discovered4 ,the cupular envelope of immature seeds1 compared by ,oliver and ,scott with the lobed and glandular husk of ,corylus colurna ,l4#aec1 receives several vascular bundles of collateral and mesarch structure from the axial strand1 and these subdivide as they ascend4 ,the glands which occur on all parts of the cupule are sessile or stalked and identical with those on the vegetative organs of ,lyginopteris4 ,assuming that pollination occurred at a comparatively early stage in the development of the seed when the cupule was still intact1 it is conceivable1 as ,sir ,joseph ,hooker suggested1 that the glandular secretion may have attracted insects and so aided in the transport of pollen which were perhaps drawn down the narrow pollen-chamber by exuded mucilage as in recent ,conifers4 ,the evidence obtained in recent years in favour of insect-pollination in certain ,cycads and in ,welwitschia lends support to this view3 the dragon flies hovering over a fertile ,lyginopteris frond in a recent restoration#aed may be a legitimate addition4 ,a striking feature of ,lagenostoma as of other ,palaeozoic seeds is the absence of an embryo3 this and other considerations have led certain authors1 notably ,chodat#aee1 to question the justification for the use of the term seed4 ,various suggestions have been offered in explanation of this fact4 ,in recent ,cycads1 as already pointed out1 the development of the embryo does not always occur before seed-fall4 ,it may be that these older seeds had no resting-period or there may have been a period of rest after fertilisation and not as now at a stage subsequent to the formation of the embryo#aef2 it is also suggested by ,scott that #8the nursing of the embryo had not yet come to be one of the functions of the seed1 and that the whole embryonic development was relegated to the germination stage#aeg4' ,in this connexion reference may be made to a statement by ,miss ,gibbs#aeh who speaks of seeds of a ,podocarpus picked up from the ground in apparently a mature state and with the associated bracts coloured and swollen as though ready to aid in dispersal but with no embryo3 the seeds had matured before fertilisation and fell from the tree after pollination4 ,whatever may be the true explanation of the absence of embryos this negative character should not be allowed to outweigh the evidence furnished by morphological features as to the applicability of the term seed4 ,as ,prof4 ,oliver says1 #8there is a long chapter in evolution to be deciphered before we can connect 444 the seed of ,lyginodendron with the sporangium of any fern at present known to us'#aei4 ,the cupule of ,lagenostoma has been homologised with the outer part of the integument of a recent cycadean seed#afj which1 it is suggested1 consists of an inner and an outer envelope that have become concrescent1 and this hypothesis is supported by another author by a comparison between ,lagenostoma and ,gnetalean seeds#afa4 ,a comparison has also been made between the collar of a ,ginkgo seed and the much more conspicuous cupule of ,lagenostoma#afb4 ,dr ,benson and ,miss ,welsford#afc institute a comparison between the vascular supply of the outer integument of the ovules of ,carpinus and ,morus and that of the cupule of ,lagenostoma1 a comparison suggested by ,miss ,kershaw's remarks#afd on the similarity between the vascular system of the ovules of ,myrica ,gale and ,trigonocarpus4 ,in #aijh ,dr ,benson#afe described some germinating microspores in the pollen-chamber of another species of ,lagenostoma1 ,l4 ovoides1 and recognised what she believed to be antherozoids4 ,i am indebted to this author for allowing me to make a drawing from her section 7fig4 #djh1 ,d74 ,two microspores are seen with thick outer walls showing irregular holes probably of secondary origin and not part of a regular reticulum as ,dr ,benson suggests4 ,close to the upper microspore is a hemispherical body1 s1 described as a male gamete1 and a similar body is seen still enclosed by the lower microspore4 ,it is by no means improbable that these are antherozoids3 they were presumably ciliate like those of ,ginkgo and recent ,cycads 7fig4 #cif1 ,m74 ,the microspores are approximately #gj in length and the supposed antherozoids have a maximum diameter of #de1 the latter being about the size of the sperms of ,microcycas and the diameter of those of ,zamia4 ,the smaller and more delicate cells near the lower microspore 7fig4 #djh1 ,d7 are no doubt fungal cells as ,miss ,benson suggests4 ,with reference to the difficulty of determining the nature of ,miss ,benson's supposed gametes it is worth calling attention to some figures given by ,zopf#aff of vesicular cells and sporangia of the ,phycomycetous genera ,rhizophidium and ,lagenidium in the pollen of ,flowering plants and ,pines4 ,it has been suggested by ,burlingame#afg that the #8gametes' may be prothallial cells2 but this is very improbable4 ,lagenostoma ovoides ,williamson4 ,in the memoir in which the genus was founded ,williamson described two species from the ,lower ,coal ,measures of ,lancashire1 ,lagenostoma ovoides and ,l4 physoides#afh4 ,the seeds described under the latter name had previously been assigned by him to another new genus1 ,physostoma1 and named ,p4 elegans#afi4 ,lagenostoma physoides was afterwards figured by ,butterworth#agj who recognised some new features4 ,for this species ,prof4 ,oliver#aga has adopted ,williamson's earlier name1 ,physostoma elegans4 ,the former species1 which has recently received exhaustive treatment by ,miss ,prankerd#agb1 agrees generally in its morphological characters with ,l4 ,lomaxi1 but differs in the structure of the surface-tissue of the integument and in some anatomical features4 ,moreover no cupules have been found and there is #8very little trace of a layer of separation' such as occurs in ,l4 ,lomaxi4 ,over the surface of the integument is a layer of prismatic cells1 much shorter and less palisade-like than those in ,l4 ,lomaxi1 and there are none of the pegs which are a constant feature in that species4 ,there are1 however1 indications that mucilage was poured out by the rupture of the distended cells4 ,some microspores were found in the pollen-chamber with an average size of #gb #ec2 they may be as much as #ij long4 ,none were observed with sperm-like contents like those described by ,dr ,benson4 ,miss ,prankerd discusses the morphology of the integument in relation to that of cycadean seeds and makes an instructive comparison between the lagenostome 7that is the modified nucellar apex7 and such fern sporangia as those of ,angiopteris1 ,osmunda1 and ,schizaea1 but especially the sporangia of ,senftenbergia#agc with their multiseriate annulus4 ,an interesting feature is shown in the longitudinal section reproduced in fig4 #dic1 ,a 7p4 #caa74 ,the apex of the nucellar cone appears to be composed of thick-walled1 dark cells and it is suggested that this may have served as a stopper blocking up the circular orifice of the pollen-chamber 7seen below the apex between the nucellar cone and the thick surface-layer of the nucellus7 and serving as a protection to the embryo4 ,a comparable closing-up of the micropyle occurs in the seeds of ,gnetum ,gnemon#agd and in the beak of cycadean seeds4 ,at the time of pollination1 when the pollen-chamber must have extended to the apex of the lagenostome1 the tip of the nucellar cone may have secreted some sticky substance to which the microspores would adhere4 ,prof4 ,lignier#age has recently described some large megasporangia from the ,westphalian ,coalfield of ,ostrau in ,austrian ,silesia which he made the type of a new genus ,mittagia1 after ,herr ,mittag1 ,director of ,mines4 ,two sporangia1 between #b and #c mm4 in diameter1 were found in close association as though belonging to a single sorus2 one was empty and the other contained four megaspores4 ,the structure of the thick wall of the sporangia is very similar to that of the testa of ,lagenostoma ,lomaxi1 but it apparently split into two valves4 ,lignier refers the new type1 ,mittagia seminiformis1 to some unknown ,palaeozoic group of heterosporous ,filicineae1 possibly the ancestral stock of the ,pteridosperms1 and he thinks it probable that the sporangia resembled seeds in their facilities for dispersal4 ,in the structure of the sporangial wall ,mittagia also resembles the sporocarp of ,pilularia4 ,seeds presented as impressions1 without internal structure1 superficially resembling ,lagenostoma4 ,lagenospermum ,nathorst4 ,this generic name is adopted for seeds represented by casts or impressions agreeing in external features with ,lagenostoma but which on the available evidence cannot be confidently assigned to that genus#agf4 ,two types of seed were described by ,arber#agg from the ,lower ,coal ,measures of ,scotland as ,lagenostoma ,kidstoni and ,l4 ,sinclairi3 the former has been removed by ,oliver#agh to ,physostoma and both are included by ,arber#agi in a recent paper in the genus ,radiospermum4 ,this new generic term is proposed by ,arber for a number of small sub-cylindrical seeds founded on impressions including #8small seeds which1 when the structure is preserved1 are known as ,lagenostoma1 ,physostoma1 and ,conostoma4' ,the question of nomenclature is invariably raised by cases in which impressions resemble in their superficial characters genera founded on anatomical characters3 the seeds originally referred to ,lagenostoma ,sinclairi afford a good example of this difficulty4 ,nathorst has recently proposed the generic name ,lagenospermum as preferable to ,lagenostoma and ,radiospermum in the case of ,lagenostoma ,sinclairi and similar seeds which afford no proof of the possession of such morphological characters as would justify their inclusion in the genus ,lagenostoma but which may be examples of that genus4 ,as ,nathorst points out1 the adoption of ,radiospermum for ,l4 ,sinclairi is inadvisable on the ground that it is also applied to seeds of a different type4 ,the type-species of ,lagenospermum is ,l4 ,sinclairi and ,nathorst describes additional species from ,lower ,carboniferous rocks in ,spitzbergen4 ,lagenospermum ,sinclairi 7,arber ex ,kidston ,,ms474 ,although it is not certain that these seeds are morphologically identical with the genus ,lagenostoma1 a brief description is intercalated here as the habit of the seed-bearing axes supplies a probable key to the habit of the fertile fronds of ,lyginopteris4 ,the type-specimens were collected by ,mr ,sinclair from the ,lower ,coal ,measures of ,ayrshire1 ,scotland1 and recorded by ,kidston as ,lagenostoma sp43 they were afterwards named by him in manuscript ,l4 ,sinclairi and handed to ,dr ,arber for description4 ,the seeds are elliptical-oblong1 #d-ee #ae-c mm41 radially symmetrical and enclosed by a loose envelope which is longitudinally ribbed and divided distally into several linear-lanceolate lobes 7fig4 #djh1 ,a1 ,a74 ,this covering1 though much longer than the cupule of ,lagenostoma ,lomaxi1 is probably a homologous structure4 ,the most interesting point is the attachment of the seeds to slender branches of a compound axis 7fig4 #djh1 ,a74 ,it is probable that the seeds were borne on a frond characterised by the reduction or complete abortion of the sterile lamina or perhaps1 as in the recent ,fern ,thyrsopteris elegans#ahj1 some of the pinnae of a large compound frond were fertile4 ,it is worthy of note that ,arber recognised pinnules of ,sphenopteris obtusiloba#aha in association with ,l4 ,sinclairi1 a fact1 as he says1 in itself of no value but which acquires significance in view of the discovery by ,carpentier#ahb of cupules in close proximity to the same species of frond4 ,specimens described by ,dr ,stopes from ,westphalian rocks of ,new ,brunswick as ,pterispermostrobus bifurcatus#ahc bear a close resemblance to ,l4 ,sinclairi4 ,lagenospermum oblongum 7,kidston74 ,the species recently described by ,dr ,kidston#ahd as ,lagenostoma oblonga from the ,south ,staffordshire coal-field appears to be closely allied to ,arber's ,l4 ,sinclairi3 it is represented by pairs of seeds borne at the ends of forked branchlets3 the seed is #be mm4 long by #ae mm4 broad and is surrounded by a longer oblong cupule divided distally into #f free lobes4 ,a larger type of seed1 #c cm4 long and #be cm4 broad1 is described by ,kidston#ahe from the same coal-field as ,lagenostoma8 urceolaris4 ,a characteristic feature is the truncate apex surrounded by a prominent canopy formed of the expanded apical free portion of the integument4 ,the lack of anatomical data in both these seeds is a reason for the substitution of some less committal term than ,lagenostoma4 ,grand',eury#ahf and ,carpentier#ahg have published accounts of impressions of seeds from the ,coal ,measures of ,france compared by them with species of ,lagenostoma though not assigned to new species4 ,these and similar seeds should be referred to ,nathorst's genus ,lagenospermum4 ,the difficulty of recognising the true nature of seed-like impressions is illustrated by some specimens in the ,goldenberg collection in ,stockholm described by ,arber#ahh as ,carpolithus ,nathorsti3 these consist of pieces of ,sphenopteris pinnae probably1 as ,zeiller suggested1 ,sphenopteris ,schaumburg-,lippeana 7,stur7 bearing at the ends of the segments of deeply divided pinnules what appeared to be seeds #a mm4 long1 oval and longitudinally ribbed1 and possibly enclosed in a cupule4 ,arber considered the #8seeds' to be related to ,lagenostoma1 probably belonging to some member of the ,lyginopterideae4 ,an examination of the specimens by ,nathorst#ahi showed that the supposed seeds are collections of spores2 but whether the spores of a true ,fern or the microspores of a ,pteridosperm cannot be determined4 ,pterispermostrobus ,stopes4 ,pterispermostrobus bifurcatus ,stopes4 ,dr ,stopes#aij has recently called attention to a resemblance between specimens from the ,westphalian of ,new ,brunswick1 described by her as ,pterispermostrobus bifurcatus1 and ,lagenospermum ,sinclairi4 ,the ,new ,brunswick fossil is made the type of a new genus ,pterispermostrobus1 which is employed for fructifications of ,pteridosperms that cannot be associated with a known species of parent and may be either seeds or complex male organs borne on a definitely branched rachis4 ,the type-species is represented by a slender axis bearing lateral branches divided into two widely divergent arms each of which bears a terminal body1 #d #c mm41 characterised by #c-e apical lobes extending #b mm4 beyond the distal end of the seed-like organ and resembling a cupule4 ,in this as in many other cases it is impossible to determine the true nature of the reproductive bodies1 whether they are small seeds or groups of microsporangia3 the new generic name serves a useful purpose though it is not always possible definitely to refer doubtful fructifications of this kind to a ,pteridosperm4 ,the organs in question may also be compared with ,codonotheca#aia4 ,pterispermostrobus pusillus 7,nathorst74 ,the name1 ,codonotheca pusilla1 is given by ,nathorst#aib to some doubtful specimens from the ,culm of ,spitzbergen representing short stalks bearing linear-lanceolate scale-like bodies1 #i-aj mm4 long by #a mm4 broad1 coalescent at the base4 ,nathorst compares them with ,sellard's species1 ,codonotheca caduca1 but adds that they may be cupules of some ,pteridosperm and calls attention to their resemblance to some fossils figured by ,carpentier as ,calymmatotheca acuta4 ,both ,nathorst's species and the ,french specimens described by ,carpentier#aic as cupules may be referred to ,dr ,stopes' genus ,pterispermostrobus as their morphological nature cannot be determined4 v4 ,roots4 ,in #ahgf ,williamson#aid described some petrified vegetative organs from the ,lower ,coal ,measures of ,lancashire under the name ,kaloxylon ,hookeri characterised by a division of the secondary xylem into cuneate masses 7fig4 #dae1 ,c7 like those in some recent ,bignoniaceous stems4 ,williamson at first believed ,kaloxylon to be a stem1 but in a later memoir he expressed the opinion that #8it is difficult to believe that these organs have been other than roots'#aie4 ,felix#aif had meanwhile described a specimen from the ,coal ,measures of ,westphalia as ,kaloxylon cf4 ,hookeri and suggested that it might be a waterplant4 ,in #ahid ,williamson and ,scott#aig demonstrated that ,kaloxylon ,hookeri is the root of ,lyginopteris1 a conclusion independently reached by ,hick#aih4 ,the roots of ,lyginopteris arise on all sides of the radially symmetrical stem in the pericycle region2 they are copiously branched as is shown by the abundance of roots of various sizes in close association4 ,no roots have been discovered exceeding #a cm4 in diameter nor have any been recorded with secondary periderm-tissue4 ,the absence of root-hairs and the more or less lacunar structure of the cortex are indicative of swampy ground4 ,it is seldom that the palaeobotanist has an opportunity of investigating the growing-points of ,palaeozoic plants1 and for this reason some well-preserved apices of ,lyginopteris roots1 attributed to that genus on the ground of constant association with fragments of stems in the calcareous nodules of ,dulesgate1 are of special interest4 ,one of these specimens was figured by ,dr ,stopes and ,mr ,watson#aii in their account of plant-bearing nodules1 and a description of that and other examples has since been published by ,prof4 ,weiss#bjj4 ,a longitudinal section of a root-tip1 #ba mm4 in diameter at its broadest part1 shows a root-cap which suggests an origin from a single cell1 but an examination of the plerome-cylinder in a slightly tangential section does not afford conclusive evidence of the occurrence of a single initial cell4 ,weiss on the whole inclines to the view that ,lyginopteris possessed a single apical cell like the roots of ,leptosporangiate ,ferns1 though he prefers to leave the decision open4 ,attention is drawn to the fact that the plate of tracheidal tissue in emerging lateral rootlets is vertical as in ,phanerogams and not horizontal as in recent ,pteridophyta4 ,the vascular tissue of a ,lyginopteris root 7fig4 #daj7 consists of from three to eight alternate strands of centripetal xylem and phloem1 and with the metaxylem is associated a small amount of conjunctive parenchyma which does not form a central pith4 ,the pericycle1 one to several layers broad1 is succeeded by an endodermis which occasionally shows the characteristic thickenings on the radial walls4 ,a broad cortex of thin-walled lacunar tissue with numerous secretory cells is bounded externally by a superficial cylinder of two or more layers of comparatively large and thin cells1 the outermost of which are radially elongated4 ,this superficial tissue forms a striking feature by which a ,lyginopteris root may often be recognised at a glance4 ,the root represented in fig4 #daj1 approximately #b mm4 in diameter1 has a heptarch stele divided into seven xylem-groups by crushed bands of parenchyma and a protoxylem strand occupies the apex of each projecting angle 7fig4 #daj1 px74 ,the superficial cylinder of clear cells is seen at a4 ,a very small root is seen at r in fig4 #daj4 ,illustration3 ,fig4 #daj4 ,lyginopteris oldhamia1 young root4 #cj4 7,kidston ,coll4 #djc47 ,fig4 #dae1 ,c1 represents part of an older root in which the pentarch primary xylem is enclosed by broad wedge-like groups of secondary xylem and phloem separated by conspicuous medullary rays opposite the protoxylem strands 7px74 ,crushed primary phloem arcs1 p1 are often clearly recognisable beyond the cambium4 ,the secondary thickening1 as ,williamson and ,scott state1 #8takes place exactly in the manner typical of roots of ,dicotyledons1 so that this fossil might very well be used for purposes of demonstration as illustrating the secondary growth of a root with diagrammatic clearness'#bja4 ,the young roots of ,lyginopteris resemble in many respects those of ,marattiaceous ,ferns1 though the presence of a single apical cell1 if such occurs1 is a distinguishing feature2 but in the presence of secondary conducting tissue they agree with those of ,phanerogams4 ,distribution of ,lyginopteris4 ,the frequency with which petrified fragments of ,lyginopteris stems occur in the calcareous nodules of the ,english coal seams shows that the genus must have been plentifully represented in the ,upper ,carboniferous vegetation1 and the occurrence in both ,north ,american#bjb and ,european localities of fronds identical with or closely resembling ,sphenopteris ,hoeninghausi affords evidence of wide geographical range4 ,petrified specimens were recorded by ,felix#bjc from ,westphalia in #ahhf1 and ,zalessky#bjd has recently discovered ,lyginopteris in the ,donetz coal-basin of ,russia4 ,an investigation by ,kubart#bje of the calcareous nodules1 to which attention was first drawn by ,stur1 in the ,ostrau ,coal ,measures led to the discovery of several examples of ,lyginopteris stems4 ,the descriptions and figures so far published are hardly sufficient to enable us to estimate the degree of relationship to the ,english type1 but some of the stems appear to be new species and ,kubart considers them all to be specifically distinct from ,lyginopteris oldhamia4 ,lyginopteris heterangioides contains scattered tracheids in the pith and thus affords an interesting transitional type between ,lyginopteris and ,heterangium4 ,in ,l4 lacunosum the inner cortex is lacunar and the primary xylem bundles pursue an independent course in the stele in contrast to the anastomosing arrangement in ,l4 oldhamia and in another ,hungarian species ,l4 tristichum4 ,the species recorded by ,kubart occur in the ,millstone grit and the ,coal ,measures4 ,the geological range of ,lyginopteris as represented by petrified stems does not extend beyond the limits of the ,carboniferous system4 ,,heterangium4 ,the generic name ,heterangium was first used by ,corda#bjf for a piece of stem from the ,coal ,measures of ,radnitz1 ,bohemia1 represented by part of the vascular axis of a stem consisting of strands of large reticulately pitted tracheids intermixed with parenchyma and exhibiting structural features differing apparently from those of any known type4 ,corda's material has been re-examined by ,kubart#bjg who figures a section from it4 ,heterangium is a genus closely allied to ,lyginopteris both in habit and in general anatomical characters4 ,the stem is monostelic2 the vascular cylinder prior to secondary thickening resembles the protostele of certain recent species of ,gleichenia and may be compared also with ,trichomanes scandens#bjh4 ,it agrees with that of ,lyginopteris in the possession of primary mesarch bundles but differs in the substitution of a cauline axial mass of metaxylem for the pith of ,lyginopteris4 ,the secondary vascular tissue agrees closely with that of recent ,cycads and ,lyginopteris4 ,a characteristic feature is the occurrence of numerous horizontal bands of sclerous cells in the cortex 7fig4 #dab7 of the stem and in the ground-tissue of the rachis and larger branches of the fronds4 ,the stem was erect and rarely branched #8giving off large foliar appendages at somewhat distant intervals and from its entire circumference'#bji4 ,our knowledge of the reproductive organs is less precise than in the case of ,lyginopteris2 but we are justified in asserting that ,heterangium is a ,pteridosperm which in all probability bore fern-like microsporangia and seeds similar in general plan to ,lagenostoma4 ,the association of some seeds included in ,williamson's genus ,conostoma with ,heterangium ,grievii in the ,pettycur beds and their resemblance to ,lagenostoma1 the seed of ,lyginopteris1 suggested the possibility of actual connexion3 further evidence in support of this view has recently been brought forward by ,dr ,benson#baj in the case of a species of ,conostoma which she transfers to a new genus ,sphaerostoma4 ,the two species ,heterangium ,grievii and ,h4 tiliaeoides are described in illustration of the genus and reference is made to a few other types4 ,heterangium ,grievii ,williamson4 7,stem47 #ahgb4 ,dictyoxylon ,grievii1 ,williamson1 ,brit4 ,ass4 ,rep4 7,edinburgh ,meeting71 p4 #aab4 #ahgc4 ,heterangium ,grievii1 ,williamson1 ,phil4 ,trans4 ,r4 ,soc4 ,vol4 #afb1 p4 #djd4 7,leaf47 #agbj4 ,fumaria officinalis1 ,volkmann1 ,silesia subterranea1 p4 #aaa1 ,pl4 xiv4 fig4 #b4 #ahbb4 ,filicites 7,sphenopteris7 elegans1 ,brongniart1 ,class4 ,vg4 p4 #bcc4 #ahbh4 ,sphenopteris elegans1 ,brongniart1 ,hist4 ,vg4 ,foss4 p4 #agb4 #ahcf4 ,cheilanthites elegans1 ,goeppert1 ,foss4 ,farnkr4 p4 #bcc4 #ahgg4 ,diplothmema elegans1 ,stur1 ,culm ,flora1 ii4 p4 #acj4 i4 ,stem4 ,at the ,edinburgh meeting of the ,british ,association ,williamson#baa gave a brief account of some petrified stems from the ,lower ,carboniferous strata of ,burntisland on the ,firth of ,forth which he included in the genus ,dictyoxylon4 ,one of these was named ,d4 ,grievii after ,mr ,grieve the discoverer of the specimens4 ,in a later and more complete description ,williamson adopted ,corda's generic name on the ground of the close resemblance of the ,scotch stem to the ,bohemian fragment ,heterangium paradoxum4 ,in #ahgcbab ,williamson added new facts in regard to ,h4 ,grievii and in #ahijbac he described a very closely allied type from the ,lower ,coal ,measures of ,lancashire4 ,five years later his descriptions were considerably extended and modified in the joint memoir with ,dr ,scott#bad4 ,the great difference in age between the ,english ,upper ,carboniferous stem and the ,scotch specimens from the ,lower ,carboniferous beds of ,burntisland suggests a probable specific difference4 ,dr ,scott has recently adopted the name ,heterangium ,lomaxi1 proposed but not published by ,williamson1 for the ,english type4 ,though in the following account the species ,heterangium ,grievii is treated in the broader sense it should be recognised that the geologically younger stem is worthy of specific recognition2 it is characterised1 to quote ,scott#bae1 by #8the great distinctness of the primary xylem strands1 by their nearly exarch structure1 with little primary centrifugal wood1 by the abundant secretory sacs of the stele1 and by the rather scattered leaves4' ,illustration3 ,fig4 #daa4 ,heterangium ,grievii4 lt1 a1 b1 c1 leaf-traces2 p1 pericycle with periderm2 ph1 phloem2 x1 x1 primary and secondary xylem2 px1 protoxylem2 r1 root2 s1 sclerous tissue4 ,heterangium ,grievii has a radially symmetrical stem bearing compound leaves with decurrent petioles which give to the otherwise cylindrical axis an angular outline as seen in transverse section 7fig4 #daa1 ,a74 ,the phyllotaxis appears to be 4 ,the stem rarely exceeds #ae cm4 in diameter3 in the centre is a comparatively large stele consisting in young stems of primary xylem and phloem1 but in older stems these are separated by a cylinder of secondary vascular tissue which in this species is always narrower than in ,lyginopteris oldhamia and1 as ,williamson pointed out1 often of unequal thickness on different radii4 ,the medullated stele of ,lyginopteris is replaced by a solid xylem-cylinder consisting mainly of groups of large tracheids1 reaching #c mm4 in diameter1 with multiseriate bordered pits 7fig4 #daa1 ,d7 embedded in an anastomosing parenchymatous tissue-system4 ,in the stele reproduced in fig4 #daa1 ,b1 which with the exception of a very narrow zone of secondary xylem1 x1 consists entirely of primary xylem1 x1 the parenchyma is represented by a darker reticulum 7cf4 fig4 #dae1 ,b7 dividing the metaxylem into islands as in ,gleichenia4 ,in the peripheral portion of the xylem the tracheids are rather narrower and arranged in more definite groups in many of which is a single strand of narrow spiral elements 7fig4 #daa1 ,a1 px7 close to the outer margin4 ,these peripheral primary bundles in which protoxylem is recognisable may be described as leaf-traces of mesarch structure consisting of centripetal xylem and1 to a much less extent1 of smaller centrifugal elements for the most part with dense spiral bands in place of the multiseriate pits of the rest of the metaxylem4 ,the structure of these leaf-traces is practically identical with that of the primary bundles of ,lyginopteris4 ,there is1 however1 a difference to which attention is drawn by ,williamson and ,scott4 ,while in ,lyginopteris in any transverse section the primary bundles in the stele are equal in number to the leaf-traces in the pericycle and cortex1 in ,heterangium the peripheral groups in the stele may be as many as twenty1 a number considerably in excess of the leaf-traces beyond the limits of the primary xylem of the stele4 ,it may be that the leaf-trace of each leaf1 which joins the stele at a distance of #f-aj internodes below its entrance into the cortex from the leaf-stalk1 may branch in its descent in the axial region1 or some of the primary groups of xylem may be confined to the axial region and independent of the leaf-traces4 ,portions of the peripheral region of the stele may be occupied by metaxylem groups without protoxylem and identical with those which make up the bulk of the metaxylem4 ,scott#baf has recently published a note in which he states that most of the ,british ,coal ,measures ,heterangiums were polydesmic4 ,two bundles1 and not a single strand as in the ,scotch ,h4 ,grievii1 leave the stele for each leaf1 and these divide into four1 in some cases at least1 before entering the petiole4 ,the secondary xylem is continuous at its inner edge with the outermost primary tracheids 7fig4 #daa1 ,a7 and consists of rows of tracheids1 #a-c elements broad1 alternating with numerous broad medullary rays of radially elongated parenchyma4 ,beyond a typical cambium-zone the secondary phloem consists of parenchyma and sieve-tubes bounded by crushed arcs of primary phloem4 ,abutting on the phloem is a pericycle composed of several layers of small parenchymatous cells 7fig4 #daa1 ,a1 p7 and in the outer layers of this tissue a phellogen 7fig4 #daa1 ,c1 p7 and some periderm are usually present though1 as ,williamson and ,scott point out1 the periderm is less regular and narrower than in ,lyginopteris4 ,the inner cortex1 composed of short parenchymatous cells1 is traversed by numerous narrow bands of dark1 thick-walled cells similar in the structure of the elements1 though peculiar in the horizontal elongation of the groups1 to the sclerous nests in the pericycle and pith of ,lyginopteris4 ,these characteristic bands are chiefly seen in the oblique longitudinal section of a stem represented in fig4 #dab4 ,in this section1 #be mm4 in length1 the lighter band1 p1 is the pericycle and in it a few obliquely cut leaf-traces are shown as dark patches4 ,the horizontal bands are similar in structure and shape to the diaphragms of thick cells in the pith of ,abies magnifica#bag1 and in both plants they probably serve as supports to the softer parenchyma4 ,there may be as many as #df bands in a vertical length of cortex of #a inch 7about #ai per centimetre74 ,it was the occurrence of precisely similar transverse lines on the carbonised impressions of the rachis of ,sphenopteris elegans that led ,kidston#bah to suggest a connexion between that species and the stem of ,heterangium ,grievii4 ,the outer cortex1 consisting of alternate strands of parenchyma and stereome similar to that of ,lyginopteris1 is much narrower and a less conspicuous feature than in ,heterangium2 the stereome bands do not form so regular a hypodermal network and extend much further vertically without anastomosing4 ,the epidermis has been described as a layer of fairly thick cells showing in one case an appearance of a depressed stoma#bai4 ,there are no secretory canals like those of ,cycads but1 as in ,lyginopteris1 scattered cells with dark contents in the stem-tissues probably represent secretory sacs4 ,the leaf-traces on leaving the stele pursue a very gradually ascending course to the petiole2 they retain their collateral structure in the pericycle and cortex and have no secondary xylem1 but become concentric as they enter the base of a leaf4 ,illustration3 ,fig4 #dab4 ,heterangium ,grievii4 ,oblique longitudinal section of stele and part of cortex2 p1 pericycle4 #c4 7,kidston ,coll4 #ebi47 ,before passing to the description of the leaves1 the more striking features in the stem may be summarised with reference to the diagrammatic sketches shown in fig4 #daa4 ,fig4 #daa1 ,a1 represents a section of ,heterangium ,grievii approximately #b cm4 in its maximum diameter2 at the periphery of the primary xylem1 x1 and close to its outer margin are several protoxylem groups1 not shown in the drawing1 each of which marks the position of a mesarch trace4 ,the zone of secondary xylem1 x1 is interrupted by the exit of leaf-traces and one of these is seen at a in fig4 #dae1 ,a1 separated from the central primary xylem by a foliar gap filled with parenchyma4 ,the pericycle is shown at p in fig4 #dab and its outer boundary at p in fig4 #daa1 ,a4 ,beyond the pericycle is the broad parenchymatous cortex with leaf-traces1 lt1 and some sclerenchymatous patches1 s4 ,the vascular strand a is passing into the base of a leaf-stalk4 ,in the stem shown in fig4 #daa1 ,b1 #ad cm4 #g mm41 a decurrent petiole is seen at the upper end with its single vascular strand1 a1 and two sclerous nests2 a similar though detached leaf-base occurs at the opposite end of the long diameter4 ,other leaf-traces are seen at b and c4 ,from the left-hand side of the stele a curved strand of tracheids is passing out to supply a root1 r4 ii4 ,root4 ,adventitious roots of endogenous origin are occasionally met with in ,heterangium stems1 but we have less information as to their anatomy than in the case of ,lyginopteris4 ,in a specimen of ,heterangium ,lomaxi figured by ,williamson and ,scott#bbj three roots are seen in a vertical series growing outwards through the cortex of a stem4 ,the roots agree generally with those of ,lyginopteris but the outermost cortical layers possess no special features4 iii4 ,leaf4 ,the large compound fronds long known as ,sphenopteris elegans were recognised by ,kidston as the leaves of ,heterangium by the closely arranged transverse striae or narrow ribs on the rachis and pinnae which are the expression on the carbonised impressions of the horizontal plates of sclerous tissue in the petrified stems and petioles of ,heterangium4 ,the dichotomously branched fronds are included by ,stur in his genus ,diplotmema and that author figures several typical examples in his #8,culm ,flora'#bba4 ,fig4 #dac1 ,a1 shows a forked axis with the bases of more slender branches and the characteristic transverse bands and in fig4 #dac1 ,b1 part of a pinna is reproduced4 ,in general appearance1 except in the bifurcating pinnae1 the fronds resemble those of ,davallia tenuifolia with which ,brongniart compared the ,palaeozoic species4 ,there is little doubt that ,sphenopteris dissecta and some other species were also borne on ,heterangium stems4 ,the rachis and petioles differ from those of ,lyginopteris fronds in the absence of emergences 7cf4 fig4 #djd1 ,e74 ,the petioles 7fig4 #daa1 ,b1 a7 have a single concentric vascular bundle with internal protoxylem4 ,illustration3 ,fig4 #dac4 ,sphenopteris 7,diplotmema7 elegans4 ,a4 ,forked rachis with bases of lateral branches 7,kidston ,coll472 ,b1 pinna4 7,after ,stur47 iv4 ,reproductive organs4 ,as yet no satisfactory evidence has been published with regard to the nature of the microsporangia but in all probability these were constructed on the same plan as those of ,lyginopteris4 ,there is a strong prima facie case for assigning the seed ,sphaerostoma to ,heterangium3 absolute proof of organic connexion is still lacking though ,dr ,benson's recent account of the seeds associated with ,heterangium ,grievii almost amounts to demonstration of continuity between vegetative organs and seeds4 ,sphaerostoma ovale 7,williamson74 ,illustration3 ,fig4 #dad4 ,sphaerostoma ovale4 ,a4 ,longitudinal section showing the cupule1 c1 integument1 e1 f1 with vascular bundle1 v1 the upper part of the nucellus1 n1 and megaspore1 m2 a1 archegonia4 ,b4 ,transverse section through the roof of the pollen-chamber1 pc1 and the summit of the nucellus1 n4 7,after ,benson47 ,in #ahgg ,williamson described some detached petrified seeds from the ,lower ,carboniferous rocks of ,fifeshire1 ,scotland1 as ,conostoma ovale and ,c4 intermedium4 ,dr ,benson's investigation#bbb of these two forms leads her to confirm ,williamson's doubts as to the validity of a specific separation and she assigns the single type to the new genus ,sphaerostoma4 ,the seeds are always associated with the vegetative organs of ,heterangium ,grievii4 ,in #aiji ,oliver#bbc expressed the opinion that the ,burntisland species of ,conostoma 7 ,sphaerostoma7 is probably the seed of ,heterangium4 ,the seed consists of a central body representing the nucellus1 an inner integument1 and an enveloping cupule or outer integument3 most specimens have lost the cupule and in this condition they are #ce mm4 long with a maximum breadth of #bb mm4 ,in the middle the seed is circular in transverse section and octagonal near the base and apex4 ,the free apical part of the integument forms a frill 7canopy7 round the micropyle and extends beyond the nucellar apex which consists of a relatively flat plinth surmounted by a central dome or lagenostome 7fig4 #dad74 ,the lagenostome is surrounded by an annular pollen-chamber on to the lower surface of which abuts the large embryo-sac1 and remains of archegonia were noticed below the pollen-chamber4 ,the roof of the chamber in the young state consists of a layer of thin-walled cells extending across the flattened apex of the nucellus1 n1 but as the pollen-chamber becomes differentiated from the nucellar tissue by the disorganisation of the zone of cells its roof-cells thicken their vertical walls and assume the structure of a multiseriate annulus1 which acts as a mechanism for opening the pollen-chamber by a circular dehiscence in such a way that the edge of the ruptured roof of the pollen-chamber slightly overlaps the periphery of the central column of nucellar tissue after it has returned to its original position subsequent to the entrance of the microspores4 ,the micropylar region is surrounded by eight lobes of the integument and each is characterised by a crest of radially elongated cells1 fig4 #dad1 f1 especially prominent on the outer side4 ,external to this is the slightly longer cupular sheath 7fig4 #dad1 c7 which may also have been lobed4 ,the surface of the integument below the terminal crests consists of a layer of cells with small papillae which eventually ruptured and discharged mucilage4 ,both integuments have a vascular supply1 that of the inner integument being represented by eight vascular bundles1 some of which were found to have mesarch xylem1 given off from the single strand in the pedicel4 ,fig4 #dad shows the apical region of a seed of ,sphaerostoma3 the flat-topped nucellar cap1 n1 is surrounded by the annular pollen-chamber1 pc1 below which are indicated the archegonia3 the wall of the megaspore 7embryo-sac7 is seen at m and external to this vascular bundles1 v1 run up the inner portion of the integument accompanied by some large cells 7aqueous tissue74 ,the elongated epidermal cells at the apices of the lobes of the integument form the frill1 f1 and at a lower level the cells of the same layer are much smaller and papillate 7e73 the outer integument1 c1 forms the so-called cupule4 ,the transverse section shown in fig4 #dad1 ,b1 is taken at the level of the roof of the pollen-chamber and of the nucellar cap2 it illustrates the contrast between the #8multiseriate annulus' and the central column of small parenchyma4 ,sphaerostoma differs from ,lagenostoma in the whorl of crests around the micropyle1 in the nearly hemispherical form of the lagenostome and in the relatively wider pollen-chamber with its peculiar form of dehiscence4 ,miss ,benson1 while regarding ,sphaerostoma as similar to ,lagenostoma in general plan1 believes the distinguishing features of the former to be such as are consistent with a more primitive form4 ,an important argument in support of connecting this seed with ,heterangium is derived from the juxtaposition of some seeds and portions of ,heterangium petioles1 a juxtaposition that is believed to demonstrate original continuity4 ,grand',eury#bbd has recorded the association of two species of leaves1 ,sphenopteris elegans and ,s4 dissecta1 with small seeds compared by him with ,lagenostoma4 ,in the absence of petrified specimens it would be practically impossible to distinguish between ,lagenostoma and ,conostoma or ,sphaerostoma4 ,carpentier#bbe has described some impressions from ,french ,westphalian beds as ,conostoma and he records cupules without seeds on fronds of ,sphenopteris obtusifolia which he speaks of as having transverse striations like those of ,heterangium4 ,dr ,kidston pointed out to me that the surface-features of the ,sphenopteris rachis are probably due to ramental scales and not to the presence of horizontal sclerous bands4 ,carpentier's seeds may be compared with ,lagenospermum ,sinclairi4 ,heterangium tiliaeoides ,williamson1 ,phil4 ,trans4 ,r4 ,soc4 ,vol4 #agh1 p4 #bhi4 ,this species1 founded by ,williamson on material from the ,lower ,coal ,measures of ,halifax1 ,yorkshire1 while agreeing in the structure of the primary stele and in the general features of the cortex with the older ,heterangium ,grievii1 is clearly distinguished by certain well-marked characters4 ,sclerous groups occur in the inner cortex as in ,h4 ,grievii but they are present also in the pericycle4 ,the peripheral leaf-traces in the stele show the mesarch structure rather more distinctly than in ,h4 ,grievii1 and the secondary xylem1 which forms a much broader cylinder than in the ,scotch type1 is divided by broad medullary rays into characteristic cuneate masses each of which rests at its base on the centrifugal tracheids of a leaf-trace strand of xylem 7fig4 #dae1 ,b74 ,the most striking distinctive feature is afforded by the secondary phloem1 which is often preserved in wonderful perfection2 this is unusually thick and owing to the tangential expansion of the principal medullary rays the secondary phloem is divided into separate masses which decrease in breadth towards the external arcs of primary phloem4 ,the triangular form of the phloem rays1 composed of tangentially stretched parenchyma1 suggested the specific name tiliaeoides on account of their striking resemblance to the rays of ,tilia4 ,the leaf-traces are nearly always in pairs as they pass out through the cortex2 they subsequently divide and appear as four vascular strands in the petiole4 ,the portion of stem reproduced in fig4 #dae1 ,b1 #h mm4 broad1 shows clearly the separation of the secondary xylem and phloem into wedge-shaped groups3 in each group there are several narrow medullary rays4 ,the extrastelar tissues are represented by a few fragments only4 ,several layers of crushed periderm occur in the pericyclic region but the more external tissues have been almost completely exfoliated#bbf4 ,illustration3 ,fig4 #dae4 ,a1 ,b1 ,heterangium4 ,a1 ,h4 ,grievii1 a1 leaf-traces4 ,b1 ,h4 tiliaeoides4 ,c1 root of ,lyginopteris4 7,a1 ,b1 ,kidston ,coll41 #ebi1 #bid2 ,c1 ,williamson ,coll41 #afca47 ,reference has already been made to ,heterangium ,lomaxi1 the ,english type originally included by ,williamson in ,heterangium ,grievii4 ,the provisional species ,heterangium cylindricum ,williamson and ,scott#bbg differs1 as ,scott says1 in no important respect from ,h4 ,lomaxi and should not be retained4 ,a new species1 ,h4 minimum ,scott#bbh1 has been founded on a very small stem from the ,coal ,measures of ,dulesgate in which the leaf-traces leave the stele as single bundles as in the ,scotch ,h4 ,grievii4 ,the ,french species ,heterangium ,duchartrei#bbi ,ren4 from ,permian rocks was originally referred by ,renault to the genus ,poroxylon3 it is represented by little more than the xylem of the stele and bears a close resemblance to ,h4 tiliaeoides4 ,heterangium punctatum ,ren4 and ,h4 ,renaulti#bcj 7,brongn47 also from the ,permian of ,france were originally placed in the genus ,lycopodium and afterwards recognised as stems of ,heterangium4 ,a fourth ,french ,permian species1 ,h4 bibractense#bca1 is peculiar in the possession of a very small primary stele encircled by deep wedges of secondary xylem1 but without more information it is impossible to speak with confidence as to its systematic position4 ,kubart#bcb has recently published brief descriptions of some stems from the ,ostrauer coal-basin in ,moravia all of which he regards as specifically distinct from the ,english types4 ,in ,heterangium ,sturi the primary xylem is almost exarch and the peripheral xylem groups are not very clearly defined3 in ,h4 alatum1 so called from the presence of lateral wings on the petioles1 the leaf-trace strands are more sharply differentiated from the rest of the stele4 ,h4 polystichum is a similar type1 and ,h4 ,andrei1 with a relatively larger amount of parenchyma in the stele and thicker stems forms an additional link between ,heterangium and ,lyginopteris#bcc4 ,prof4 ,johnson#bcd has described a species of ,heterangium1 ,h4 hibernicum1 from ,upper ,devonian and ,lower ,carboniferous beds in ,co4 ,cork1 ,ireland1 based on some impressions of frond fragments without any pinnules4 ,the occurrence of numerous transverse striae on the rachis and lateral branches suggests comparison with ,heterangium fronds1 but an examination of the specimens led me to suspect that some at least of the striae are cracks and not original features4 ,the presence of spur-like appendages from the lower surface of the pinnae near their origin from the rachis is recorded as a peculiar character1 and some obscure oval bodies1 the nature of which is extremely doubtful1 are considered to be seeds4 ,the imperfection of the material hardly justifies the institution of a new species of ,heterangium4 ,heterangium ranges from the ,lower ,carboniferous to the ,permian strata and is thus older than ,lyginopteris which in the form of petrified stems is not recorded from the ,lower beds of the ,carboniferous system4 ,heterangium has been described as having a #8great preponderance of fern-like characters1' but having regard to the resemblance of the primary xylem of the latter to that of the ,osmundaceae it would seem doubtful whether in their relation to the ,ferns there is any important difference4 ,heterangium may safely be spoken of as the more primitive genus4 ,the polydesmic character of the petioles of most species is particularly interesting as it brings the genus nearer to the ,medulloseae and to ,rhetinangium#bce4 ,,chapter ,,xxx4 ,,ii4 ,,medulloseae4 ,the term ,medulloseae was first employed by ,goeppert and ,stenzel#bcf for a family of ,palaeozoic plants that appears to have reached its maximum development in the ,permian period3 the oldest representatives so far discovered are of ,upper ,carboniferous age4 ,our knowledge of the family is chiefly derived from a study of the anatomical characters of stems1 and it is therefore on this basis that any grouping of genera or species should be attempted4 ,although there is little information with regard to the reproductive organs of ,medullosa1 the type-genus1 it is certain that the ,medulloseae are ,pteridosperms differing from members of that group included in the ,lyginopterideae in the presence of more than one stele in the stem1 in the habit of the fronds1 and in the structure of the rachis1 as also in the structure of the seeds1 though these organs bear a fairly close resemblance to the seeds of ,lyginopteris and ,heterangium4 ,the fronds of the ,lyginopterideae are of the ,sphenopteris type while in the case of such species of ,medullosa as afford evidence of connexion between stems and leaves the latter have the characters of ,neuropteris1 ,alethopteris1 ,odontopteris1 ,linopteris1 and other form-genera usually included in the ,neuropterideae4 ,dr ,lotsy#bcg speaks of ,lyginopteris and ,heterangium as members of the ,sphenopteridophylla and assigns species of ,medullosa either to the ,neuropteridophylla or to the ,pecopteridophylla1 the latter subdivision including species with fronds of the ,alethopteris type4 ,there is1 however1 little doubt that other forms of leaves1 such as ,odontopteris and possibly ,taeniopteris1 were borne on ,medullosan stems4 ,it is undesirable except in the absence of more trustworthy criteria to make use of so protean a feature as leaf-form as a basis of classification4 ,the name ,neuropterideae has been frequently employed for ,pteridosperms other than the ,lyginopterideae on the ground that the foliage of ,medullosa is represented by species assigned to form-genera included in the ,neuropterideae4 ,it is1 however1 preferable to restrict the family-name ,neuropterideae to fronds and to speak of the second family of ,pteridosperms as the ,medulloseae1 including the genera ,medullosa1 ,sutcliffia1 and ,rhexoxylon4 ,,medullosa4 ,some species of ,medullosa probably resembled in habit ,angiopteris evecta and the larger ,marattias2 they had short and relatively thick stems clothed with the large decurrent bases of long compound fronds superficially like those of some recent ,ferns and the leaves of the ,cycad ,bowenia4 ,it is probable that1 as ,zeiller#bch has pointed out1 the fronds of ,medullosa and of other ,pteridosperms had a greater tendency than those of true ,ferns to a dichotomy of the rachis4 ,in other types the stems reached a considerable length and leaves and branches were separated by several feet of bare stem4 ,the large size of the leaf-stalks in proportion to the diameter of the stem as shown by such species as ,medullosa anglica and ,m4 ,leuckarti 7fig4 #daf7 suggests either a short and thick main axis or1 in the case of long stems bearing scattered leaves1 a plant that supported itself partially at least by a habit of growth comparable with that of tropical ,aroids or other lianes4 ,while ,medullosa anglica with its contiguous leaf-bases affords an example of the first type1 the occurrence of stems of a ,permian species1 ,m4 stellata1 #c metres long without branches or leaf-scars1 suggests the habit of a liane2 similarly a specimen of ,medullosa ,leuckarti in the ,chemnitz ,museum bearing a few spreading petioles but little narrower than the stem and given off at a wide angle would seem to favour the view that some species were ill adapted to be mechanically self-supporting plants4 ,the longest piece of stem that has come under my notice is a specimen of ,m4 stellata in the ,chemnitz ,museum reaching a length of nearly #h metres3 some species attained a diameter of about #ej centimetres4 ,medullosa is always polystelic3 the plan of the vascular system varies considerably as regards both the number and form of the steles1 but there is a uniform type of structure within the limits of each stele that recalls the single stele of ,heterangium4 ,the steles consist of a central region composed of primary xylem1 originally surrounded by phloem1 which in its mesarch or exarch structure agrees with the vascular tissue of some species of ,gleichenia or ,lygodium4 ,to this central region a cambium added secondary xylem and phloem either in the form of a cylinder of uniform breadth1 or more frequently the centrifugally developed xylem exceeded in amount the secondary conducting tissue added to the inner side of the primary region4 ,apart from anatomical details a ,medullosan stem with its several steles1 each with secondary tissue1 embedded in parenchymatous ground-tissue resembles the stems of some ,dicotyledonous climbers such as ,thinouia scandens1 species of ,serjania and ,paullinia#bci4 ,anatomically the main features of the stelar system of ,medullosa1 neglecting the secondary xylem and phloem1 are in closer agreement with the stems of ,ferns than with those of any other plants4 ,it has been shown that the genus ,heterangium bears a close resemblance to ,gleichenia in the structure of the primary stele 7fig4 #dah1 ,c73 one of the oldest types of ,medullosa1 ,m4 anglica1 may be described as a ,heterangium with three steles and may be compared with a dictyostelic ,fern in which the irregular vascular framework is made up of three main strands4 ,in certain types of ,medullosa 7fig4 #daf7 the ground-plan of the vascular system recalls that of a solenostelic ,fern1 while in others the greater complexity suggests comparison with such ,ferns as ,matonia1 ,angiopteris1 ,psaronius1 or ,cyathea2 #8it is as though ,nature were at the ,carboniferous moment in the midst of a series of amazing engineering experiments1 most of which were either buried deep in ,palaeozoic oblivion1 or permitted to survive only as vestigial relics and atavistic ghosts'#bdj4 ,though many ,medullosae resemble ,ferns there is an important difference between the two groups in the origin of the various plans of ,medullosan stelar systems3 in ,ferns the leaf is the determining factor in the evolution of stelar arrangement1 while in ,medullosa the occasional interruption of a solenostele or the development of an apparently complex dictyostele are features independent of the leaf and leaf-traces4 ,in the structure of the secondary xylem and phloem and in root-structure ,medullosa agrees with recent ,cycads4 ,the genus is in short a generalised type with filicinean and cycadean affinities4 ,in the possession of seeds borne on modified pinnae of compound fronds1 ,medullosa resembles both ,cycas and the ,lyginopterideae4 ,the seeds exhibit a fairly close agreement with those of ,lyginopteris1 ,heterangium and recent ,cycads1 but they appear to have advanced further towards the cycadean type than is the case with the closely related seeds of the ,lyginopterideae4 ,the microsporophylls are very imperfectly known but they were undoubtedly much less advanced and more fern-like than the megasporophylls4 ,the genus ,medullosa is recorded from the ,permian strata of ,saxony1 ,france1 and ,bohemia#bda2 also from the ,coal ,measures of ,england1 and the discovery of petrified petioles of ,myeloxylon1 the type borne on ,medullosan stems in ,european species1 may be taken as evidence of the existence of the genus in ,north ,america during the ,carboniferous period#bdb4 ,the name ,medullosa was applied by ,cotta#bdc to three types1 ,medullosa elegans1 ,m4 stellata1 and ,m4 porosa1 from the ,rothliegende of the ,chemnitz district4 ,the first of these was recognised by ,brongniart#bdd as a distinct genus for which he proposed the designation ,myeloxylon and this was afterwards identified by ,renault1 ,williamson1 and other palaeobotanists as a petiole and not a stem4 ,further reference is made to ,myeloxylon on a later page4 ,cotta spoke of ,medullosa as the most puzzling of the genera dealt with in his #8,dendrolithen1' and in spite of the many additions to our knowledge the position of this ,palaeozoic genus is still a fertile source of speculation4 ,the generic designation ,medullosa is applied to stems1 with or without petioles2 petioles or rachises of fronds that frequently occur apart from stems are referred to the genus ,myeloxylon4 ,the leaves of ,medullosa include several well-known species of ,carboniferous and ,permian genera such as ,alethopteris1 ,neuropteris and others that have in recent years been transferred from the ,filicales to the ,pteridosperms4 ,in a few instances seeds have been found in organic connexion with ,medullosan foliage1 and there can be no reasonable doubt that ,trigonocarpus1 some forms of ,rhabdocarpus1 ,pachytesta1 and other seeds represent the integumented megasporangia of ,medullosa or some closely allied genus4 ,before attempting to summarise the salient features of ,medullosa a description of a few selected types will serve to place us in a better position to consider the genus as a whole4 ,the ,british species are placed first on the ground that they are both geologically the oldest though1 historically1 the most recently described1 representatives of the genus2 and in the organisation of the stem they are simpler than the continental species4 ,their resemblance to ,heterangium serves to some extent to bridge the gap between the majority of species of ,medullosa and the simpler types of ,pteridosperms represented by ,heterangium and ,lyginopteris4 ,medullosa anglica ,scott#bde4 ,prior to the discovery of this species the genus ,medullosa had not been recorded from ,britain4 ,a section in the ,williamson collection recognised by ,scott as that of a ,medullosa had been identified by ,williamson as a large ,heterangium stem4 ,an undescribed specimen was found by ,arber#bdf in the ,binney collection at ,cambridge which afforded some additional information as to the structure of the roots4 ,the specimens on which ,scott's thorough description is based were obtained by ,messrs ,wilde and ,lomax from the ,lower ,coal ,measures of ,lancashire4 ,the stem of this oldest species has the habit of a tree-fern and is almost completely invested by the stout decurrent bases of the petioles of large spirally disposed compound fronds with a phyllotaxis of 1 the leaves of the same orthostichy being separated from one another by a vertical distance of approximately #aj cm4 ,a transverse section of a slightly flattened stem is shown in fig4 #daf1 ,a1 the bases of three petioles give to it an angular form4 ,its dimensions are approximately #aj #d cm4 ,the ground-tissue of two of the petioles is continuous with that of the stem1 while that of the third leaf-stalk is cut through near its separation from the stem and its adaxial face is already defined by a hypodermal band of stereome1 d4 ,the surface of the stem is characterised by fine longitudinal ribs caused by the slightly projecting stereome in the outer cortex1 and from the narrow furrows between the leaf-bases adventitious roots emerge in vertical series4 ,the position of an interfoliar furrow is shown by a small arrow in fig4 #daf1 ,a4 ,there are three steles1 #b-c cm4 #f-aj mm4 in diameter3 each agrees very closely in structure with the single stele of ,heterangium4 ,medullosa anglica may be described as a polystelic ,heterangium and as having the same relation to ,heterangium as regards the stelar system as ,primula auricula bears to the monostelic ,primula4 ,the central core of the stele 7the black patches in the diagram1 fig4 #daf1 ,a7 consists of an anastomosing system of tracheal groups embedded in an irregular parenchymatous reticulum4 ,the large primary tracheids reach a diameter of #aej and have multiseriate pitting3 at the periphery of the primary xylem there is a more definite grouping of tracheids as in ,heterangium1 and the slightly internal 7mesarch7 protoxylem elements are associated with scalariform and densely spiral tracheids 7fig4 #daf1 ,b1 ,c7 narrower than the more internal reticulate elements4 ,the secondary xylem is manoxylic as in ,cycads1 tracheids in #b-d radial series alternating with medullary rays #a-c cells broad and usually of considerable depth 7fig4 #daf1 ,b74 ,the principal rays are continuous with the parenchymatous matrix of the central core4 ,thick-walled tubular elements1 no doubt of the nature of sieve-tubes1 form a conspicuous feature in the phloem4 ,the three steles occasionally divide and fuse with one another4 ,the tissue between the steles is crushed and disorganised and in the living plant was probably small in amount4 ,in the imperfectly preserved inner cortical region there is a sinuous band of secondary parenchyma 7periderm2 fig4 #daf1 ,a1 c7 developed from a deep-seated phellogen2 in older stems this formed the superficial tissue after the fall of the leaves4 ,there is no definite boundary between the cortex of the stem and the petiole-bases except when the hypoderm cuts across the cortex preparatory to the separation of a leaf-stalk4 ,the stem-cortex and the ground-tissue of the petioles consist of parenchyma with numerous secretory canals1 not sacs only as in ,heterangium1 and are abundantly supplied with scattered vascular bundles of collateral and exarch structure4 ,illustration3 ,fig4 #daf4 ,medullosa stems4 ,a-,c1 ,medullosa anglica2 ,a1 transverse section2 a1 accessory vascular strand2 b1 accessory strand enclosed by periderm2 c1 band of periderm encircling steles2 d1 sclerenchyma between leaf and stem4 ,b and ,c1 longitudinal sections4 7,after ,scott47 ,d1 ,medullosa stellata2 a1 star-rings2 p1 #8partial pith4' 7,after ,weber and ,sterzel47 ,e1 ,medullosa ,solmsi4 7,after ,weber and ,sterzel47 ,f1 ,medullosa stellata1 from a specimen in the ,british ,museum 7,no4 #acgfg74 ,g1 ,medullosa stellata var4 cortica2 v1 leaf-bundles4 7,after ,weber and ,sterzel47 ,h1 ,i1 ,medullosa ,leuckarti4 7,after ,weber and ,sterzel and ,solms-,laubach47 ,k1 ,medullosa stellata var4 gigantea2 a1 concentric stele2 b1 b1 later cylinders of centrifugal tissue4 7,adapted from ,weber and ,sterzel47 ,l1 ,medullosa ,solmsi var4 lignosa4 ,m1 ,medullosa porosa4 7,l1 ,m1 after ,weber and ,sterzel47 ,the leaf-traces are furnished by the peripheral tracheal groups at the free surface of the primary portion of each stele3 each trace is at first concentric and consists of primary xylem with one or more protoxylem strands near the outer surface and is completely or partially enclosed by secondary xylem and phloem4 ,in the course of its passage to the leaf a leaf-trace loses its secondary tissues1 which were added by the cambium during the traverse of the zone of secondary wood1 and divides into small collateral bundles consisting mainly of spiral and scalariform tracheids4 ,the collateral bundles accompanied by some narrow fibres are of the ,myeloxylon type 7fig4 #dbj71 the xylem being wholly centripetal4 ,in the behaviour of the leaf-traces and in the vascular system of the petioles ,medullosa differs from ,heterangium and ,lyginopteris4 ,each leaf-base is supplied by sets of vascular strands which pass into it from the stem at different levels2 a large leaf-base reaching #d cm4 in diameter receives as many as #gj-hj bundles4 ,the hypoderm is like that first described in the ,french species ,myeloxylon ,landriotii#bdg and often spoken of as the ,sparganum type of hypoderm4 ,the branching of the rachises points to a compound frond1 and the occurrence of numerous linear pinnules with revolute margins 7fig4 #dbj1 ,d7 in association with the stem suggests that the ultimate segments were of the ,alethopteris form4 ,this inference receives confirmation from the occurrence of petrified specimens of undoubted ,alethopteris rachises with the structure of ,myeloxylon4 ,it is practically certain that the leaves borne on the stems of ,medullosa anglica are those long known as ,alethopteris lonchitica 7,vol4 ii4 ,a1 p4 #eec1 fig4 #cfd74 ,an interesting feature in the stems is the occurrence of cortical vascular strands 7fig4 #daf1 ,a1 a1 b71 reaching a diameter of #g mm41 containing scattered tracheids in a parenchymatous core surrounded by secondary xylem and phloem4 ,these cauline bundles are almost identical both in structure and distribution with the accessory steles in the stem of a recent ,cycas1 and the agreement is emphasised by the presence of short square-ended tracheids in the primary xylem4 ,the roots branch freely and may attain a diameter of more than #a cm43 they are generally triarch and the triangular primary xylem is enclosed by secondary xylem except opposite the protoxylem4 ,the cortex is like that of ,lyginopteris roots and a conspicuous double layer of superficial tissue is another feature common to both 7cf4 fig4 #daj74 ,the exceptionally well preserved specimens described by ,arber#bdh show very clearly the thick zone of periderm which forms the covering of older roots1 and in some of the sieve-tubes groups of dark brown patches show the form and arrangement of the sieve-plates4 ,reproductive organs4 ,we have as yet no precise information in regard to the reproductive organs of ,medullosa anglica1 but there can be little or no doubt that the fronds bore seeds that have long been known under the generic name of ,trigonocarpus4 ,many years ago ,mr ,hemingway noticed the almost constant association of the fronds of ,alethopteris lonchitica with ,trigonocarpus1 and ,dr ,kidston's discovery#bdi of seed-bearing ,neuropteris pinnae considerably strengthened the evidence derived from mere association4 ,the structure of ,trigonocarpus is described later 7p4 #aag7 in a section devoted to reproductive organs attributed to ,medullosa4 ,nothing is known as to the microspore-bearing organs4 ,while in the structure of each of the steles ,medullosa anglica agrees very closely with ,heterangium1 it differs from that genus in the presence of three steles and in the structure of the petioles which are much less fern-like than the simpler petioles of ,heterangium and ,lyginopteris4 ,from the continental species the ,british species is distinguished by its simpler stelar system1 though there is a close correspondence as regards individual steles4 ,medullosa pusilla ,scott4 ,this species1 briefly referred to by ,scott in #aijibej and fully described in a recent paper#bea1 is founded on material from the ,lower ,coal ,measures of ,colne1 ,lancashire4 ,it agrees in essential features with ,medullosa anglica1 but differs in the following particulars3 the linear dimensions of the stem are about one quarter those of a typical stem of the older species2 the leaf-traces possess little or no secondary xylem and the relatively large decurrent leaf-bases have a narrower and simpler hypoderm4 ,the stem has a tri-stelar vascular system enclosed in a ring of internal periderm1 and each stele 7#c mm4 in diameter7 consists of a roughly triangular strand of reticulate tracheids and a small amount of scattered parenchyma4 ,the protoxylem is either exarch or1 as in ,m4 anglica1 mesarch1 the exact position being difficult to determine in the available material4 ,the secondary xylem closely resembles that of ,m4 anglica4 ,scott suggests the possibility that ,alethopteris decurrens may be the foliage of ,medullosa pusilla4 ,it is possible that there is no specific difference between ,m4 pusilla and ,m4 anglica1 but on the present evidence the employment of a distinctive name is desirable4 ,medullosa centrofilis de ,fraine4 ,this species was founded by ,miss de ,fraine#beb on a petrified stem from the ,lower ,coal ,measures of ,lancashire4 ,the maximum diameter of the flattened stem including four decurrent leaf-bases is #e cm4 ,the vascular system consists of an outer group of four steles1 reduced to three by fusion in the upper part of the specimen1 enclosing a central smaller stele or star-ring 7fig4 #dag74 ,it is the presence of the star-ring that distinguishes this type from the other two ,british species and forms a connecting link with certain continental ,medullosae4 ,the peripheral steles agree with the steles of ,m4 anglica but1 as in ,m4 pusilla1 there is some doubt as to the exarch or mesarch position of the protoxylem4 ,in the structure of the xylem the central stele conforms to the rest of the vascular system and a strand of protoxylem is preserved that is almost certainly exarch4 ,there is evidence that the peripheral steles occasionally anastomose1 but the central stele follows an independent course at least in the piece of stem examined4 ,leaf-traces are furnished by the primary xylem of the outer steles1 and they appear to be without secondary tracheids as in ,m4 pusilla4 ,a zone of secondary cortex encloses the vascular system as in the other ,british stems3 it is pointed out by ,miss de ,fraine#bec that this tissue1 usually described as a deep-seated periderm1 must have differed from cork in that there is no sign of drying up or decay in the tissues external to it4 ,the leaf-bases are of the usual ,myeloxylon type4 ,in size this species is intermediate between ,medullosa anglica and ,m4 pusilla4 ,illustration3 ,fig4 #dag4 ,medullosa centrofilis4 ,transverse section showing the deep-seated #8periderm' 7broken line7 surrounding four steles4 7,after de ,fraine47 ,medullosa stellata ,cotta4 ,cotta#bed described ,medullosa stellata as a stem characterised by the occurrence of several many-rayed stellate columns 7#8vielstrahlige ,sternsule'7 in a pith enclosed by a double cylinder of secondary xylem4 ,the so-called pith is the central ground-tissue of the stem and the double #8striated ring' of ,cotta is a cylindrical stele identical in structure with each of the steles of ,medullosa anglica but having a tubular form instead of forming a relatively broad and short band 7cf4 fig4 #daf1 ,d and ,a74 ,goeppert#bee in his ,permian ,flora gave a detailed account of the species1 some of his sections being cut from ,cotta's material1 and by the employment of varietal epithets emphasised the range of variation within the limits of the type4 ,goeppert and ,stenzel#bef and1 several years later1 ,weber and ,sterzel#beg adopted the same plan as a convenient method of drawing attention to differences in anatomical characters4 ,as ,schenk#beh pointed out1 there is a considerable risk in the case of small pieces of stems of attaching excessive importance to structural variations1 and it is by no means improbable1 as he said1 that differences which are the expression of states of preservation or stages in development have been incorrectly regarded as distinguishing marks of individual plants4 ,it is1 however1 convenient to recognise some of the more striking deviations from the type-species by speaking of the different forms as varieties though1 as ,weber and ,sterzel fully admit1 such varieties and even some of the species must be looked upon as provisional4 ,weber and ,sterzel give expression to the provisional nature of their grouping by classifying the species with their varieties into form-cycles4 ,under the form-cycle ,medullosa stellata five more or less well defined forms are recognised1 the type-species being ,medullosa stellata var4 typica#bei4 ,medullosa stellata var4 typica4 ,part of a transverse section of a cylindrical stem is represented diagrammatically in fig4 #daf1 ,d4 ,very little of the cortex is preserved3 a parenchymatous axial region with scattered secretory canals contains four oval or cylindrical vascular steles1 the stellate columns of ,cotta or star-rings of later authors4 ,these are of the same nature as the small central stele in the ,english ,medullosa centrofilis4 ,the central region of the stem in this specimen is completely surrounded by a narrow cylinder of inversely orientated secondary xylem and phloem 7fig4 #daf1 ,d71 the phloem being on the inner side of the xylem4 ,beyond the xylem is a parenchymatous band containing scattered groups of primary xylem tracheids with spiral1 scalariform1 and reticulate pitting1 and this zone1 which is usually designated the #8partial pith1' is succeeded by a second and broader1 normally orientated1 cylinder of secondary xylem and phloem4 ,in this section the two concentric cylinders separated by the partial pith form a solenostele like that of several recent ,ferns except in the presence of secondary tissue4 ,the term #8partial pith' applied to the tissue between the two cylinders of secondary tissue is misleading3 this tissue 7fig4 #daf1 ,d1 p7 is the primary xylem of the stele and is homologous with the primary portion of the stele of ,heterangium and of the steles of ,m4 anglica4 ,in many sections the continuity of the tubular stele is broken4 ,in a section in the ,british ,museum cut from one of ,cotta's specimens#bfj1 #f #ce cm4 in diameter to the outer edge of the vascular tissue1 the cylindrical stele is interrupted at two places4 ,an example of the interrupted type of stele is shown in fig4 #daf1 ,f1 and in fig4 #daf1 ,h3 the latter belongs to a distinct species4 ,the complete type of cylindrical stele is exceptional and occurs occasionally at different levels in the stem4 ,an important point is that the frequent breaks in the cylinder are not connected with the exit of leaf-traces and do not1 therefore1 correspond to the foliar gaps in the solenostele or dictyostele of a ,fern4 ,the secondary xylem is of the cycadean type 7fig4 #dah1 ,b1 ,d7 like that of ,heterangium and ,lyginopteris and several other stems4 ,each of the star-rings in the axial region consists of a parenchymatous core with scattered primary tracheids enclosed by secondary vascular tissue 7fig4 #dah1 ,b74 ,the star-ring shown in fig4 #dah1 ,b1 from a ,chemnitz stem illustrates the characteristic cycadean character of the secondary xylem with broad medullary rays3 some of the innermost elements are in contact with the primary tracheids4 ,the phloem is rendered conspicuous by the black contents in some of the elements4 ,both the star-rings and the larger peripheral steles are constructed on the same plan and agree with the steles of ,m4 anglica4 ,the star-rings occasionally branch and anastomose with one another and with the encircling stele4 ,the star-ring in fig4 #daf1 ,d at a is about to give off a small strand4 ,leaf-traces are furnished by the primary xylem at the edge of the #8partial pith' of the outer stele3 as a leaf-trace passes outwards through the outer cylinder of secondary xylem the cambium invests it with secondary xylem and phloem1 but as it passes through the cortex of the stem it becomes reduced to its primary elements1 and by successive branching gives rise to small collateral bundles which enter the petioles4 ,the piece of stem shown in fig4 #daf1 ,g1 illustrates the exit of leaf-traces from the stele and their subsequent division into several small bundles1 v1 which are scattered in the cortex with strands of sclerenchyma4 ,in a specimen identified with ,medullosa stellata1 ,schenk#bfa found part of a leaf-base attached to the stem3 its vascular system was of the ,myeloxylon type1 the bundles being identical with those in the cortex of the stem seen in fig4 #daf1 ,g4 ,in some stems of ,m4 stellata the outer1 centrifugally developed1 portion of the main stele is very much broader than in the example represented in fig4 #daf1 ,d4 ,the diagrammatic sketch reproduced in fig4 #daf1 ,f1 represents a section of a ,chemnitz specimen in the ,british ,museum#bfb in which the axial region containing several star-rings is almost enclosed by an inner zone of secondary xylem1 and beyond the narrow primary xylem 7black in the sketch7 the rest of the block consists exclusively of secondary xylem #ee cm4 broad4 ,this example illustrates a common tendency in ,medullosa towards a large excess of centrifugal over centripetal secondary vascular tissue4 ,a similar specimen of ,medullosa stellata is figured by ,mougeot#bfc from the ,vosges showing a considerable development of centrifugal xylem comparable with that in the ,british ,museum stem4 ,weber and ,sterzel#bfd describe stems of ,medullosa stellata showing slight periodic swellings which it is suggested1 though there is no evidence in support of the opinion1 may be connected with reproductive organs4 99 99 99 99 99 ,medullosa stellata var4 corticata#bfe4 ,the specimen referred to this variety1 represented in fig4 #daf1 ,g1 has already been quoted as affording data with regard to the origin and behaviour of the leaf-traces4 ,in this type of stem the outer portion of the main stele is narrower than in ,m4 stellata var4 typica and the stele never forms a complete tube4 ,the star-rings in the centre of the stem are more numerous than in the type-species of the genus4 ,in the axial region of some stems included in the form-cycle to which ,m4 stellata belongs there may be flatter and tangentially elongated vascular strands in addition to the cylindrical star-rings2 these are termed plate-rings4 99 99 99 99 99 ,in ,medullosa stellata var4 lignosa#bff the outer xylem reaches a breadth of #d cm4 and the star-rings are reduced to one4 ,the form ,m4 stellata var4 gigantea#bfg 7fig4 #daf1 ,k7 is of special interest as an example of a stem reaching a diameter of nearly #ej cm4 and having as many as #dc large and small star-rings in the axial region4 ,a large tubular stele like that of the type-species 7fig4 #daf1 ,d7 surrounds the central region1 but in this form the cylindrical stele a is succeeded by concentric cylinders of normally orientated xylem and phloem 7fig4 #daf1 ,k1 bb7 produced by successive cambiums either cortical or pericyclic in origin4 ,this type of stem presents a striking resemblance to stems of ,cycas and ,macrozamia except in the possession of a double cylindrical stele consisting of both centripetal and centrifugal secondary xylem and phloem separated by a zone of primary xylem 7partial pith74 ,medullosa gigas ,renault4 ,this species was founded on a piece of stem from the ,permian of ,autun#bfh1 consisting almost entirely of secondary xylem1 which ,brongniart had previously placed in his genus ,palaeoxylon#bfi4 ,the secondary xylem reaches a diameter of #de-ej cm4 and in the portion of the central region preserved there are a few vascular strands like the star-rings of other species4 ,the considerable development of secondary xylem indicates a form of stem similar to some forms of ,m4 stellata 7e4g4 fig4 #daf1 ,f71 but as the available data are insufficient for accurate determination ,renault's specific name is retained4 ,renault describes the internal xylem cylinder 7i4e4 the centripetal xylem7 as very slightly developed or as hardly visible1 a feature in which the ,french specimen shows a nearer approach to the structure of a recent ,cycad4 ,medullosa porosa ,cotta4 ,the second of ,cotta's species#bgj1 which has been fully investigated by ,weber and ,sterzel1 is constructed on the same plan as that of ,m4 stellata1 but the stem is distinguished by the greater number of star-rings and1 more especially1 by the presence of an outer system of vascular strands in the axial region 7fig4 #daf1 ,m73 these form a frequently interrupted cylinder of anastomosing strands characterised by the feeble development of secondary xylem and phloem or by the absence of this tissue on the outer face of the strands4 ,the component parts of this outer series occasionally fuse with the internal star-rings4 ,medullosa ,solmsi ,schenk#bga var4 typica ,web4 and ,ster4#bgb ,this type has a large axial region containing several very small star-rings enclosed by two concentric zones of separate plate-rings 7fig4 #daf1 ,e7 each consisting of a complete flattened cylinder of secondary xylem and phloem enclosing primary xylem4 ,as the complete cylindrical stele of the stem of ,medullosa stellata shown in fig4 #daf1 ,d1 was compared with the solenostele of a ,fern1 so in this stem 7fig4 #daf1 ,e7 the vascular cylinder may be compared at least superficially with a dictyostele4 ,from the inner circle of plate-rings strands are given off in the form of star-rings and these pass through the gaps in the outer system1 eventually breaking up in the cortex into numerous collateral bundles4 ,in another form of this species1 var4 lignosa 7fig4 #daf1 ,l71 the axial region is enclosed by a circle of plate-rings like those in the type-form1 but these are succeeded by a circle of very asymmetrically developed and large steles with the outer xylem and phloem much broader than the inner4 ,moreover in this form additional cylinders of normally orientated vascular tissue are added as in ,m4 stellata var4 gigantea and in some recent ,cycads4 ,it is noteworthy that the secondary wood of ,medullosa ,solmsi is rather more compact than in other species1 a feature in which it to some extent agrees with the ,south ,african genus ,rhexoxylon4 ,medullosa ,leuckarti ,goeppert and ,stenzel4 ,in this species#bgc1 also from the ,permian of ,saxony1 the central region including some star-rings is surrounded by sinuous flattened concentric steles 7snake-rings7 agreeing anatomically with the steles of other species and characterised by the comparatively small breadth of the secondary xylem and phloem 7fig4 #daf1 ,h74 ,leaf-traces are given off1 as in ,m4 anglica and other species1 from the outer edge of the primary xylem4 ,in some forms there is a single set of snake-rings2 in others there is a double series4 ,fig4 #dah1 ,d1 shows part of the secondary xylem of a stele of this species from ,chemnitz3 the tracheids are in some places continuous with the primary xylem1 and on the outer edge of the secondary wood is a cylinder of phloem4 ,a section of ,medullosa ,leuckarti figured by ,goeppert and ,stenzel#bgd shows some radial rows of very thick-walled elements in the secondary phloem which they describe as bast sclerenchyma1 but ,solms-,laubach#bge believes them to be sieve-tubes4 ,precisely similar elements are figured by ,scott#bgf in ,m4 anglica and as this author suggests the thick walls are probably not an original feature4 ,the structure of the primary xylem is more clearly seen in fig4 #dah1 ,c1 and the relation between primary and secondary xylem is shown in fig4 #daf1 ,i1 where the position of the protoxylem may be either exarch or mesarch4 ,the protoxylem is only occasionally recognisable but some of the peripheral primary tracheal groups are undoubtedly mesarch4 ,external to the stele1 a part of which is reproduced in fig4 #dah1 ,d1 are strands of stereome elements and beyond them a band of radially elongated cells that may be #8periderm'3 still farther out there are some imperfectly preserved vascular bundles that are leaf-traces4 ,this species is important as affording a complete demonstration of the organic connexion between the stem and petioles of the ,myeloxylon ,landrioti type which indicate that the fronds were probably ,alethopteroid4 ,illustration3 ,fig4 #dah4 ,a1 ,myeloxylon radiatum1 part of petiole4 ,b1 ,medullosa stellata2 star-ring2 #ad4 ,c1 ,d1 ,medullosa ,leuckarti2 ,c1 primary xylem2 ,d1 part of primary stelar tissues and secondary xylem and phloem2 #f4 7,a-,d1 ,kidston ,coll41 #ajad1 #acjg1 #abch47 ,the specimen on which the diagrammatic drawing reproduced in fig4 #dai is based has been investigated by ,weber and ,sterzel#bgg and by ,solms-,laubach#bgh4 ,the figure is a slightly simplified version of that given by ,weber and ,sterzel2 it represents the stem of ,medullosa ,leuckarti as a transparent object1 the two lower transverse sections1 ,b and ,c1 being seen in perspective through the longitudinal faces4 ,the steles are shaded obliquely in the longitudinal sections1 and in the three transverse sections1 ,a1 ,b1 ,c1 the primary xylem 7partial pith7 is black and the enclosing secondary vascular tissue radially shaded4 ,the whole block is #i cm4 in length and #f cm4 broad4 ,only a part of the axial region is shown internal to the peripheral snake-rings and in it are the star-rings ,s1 ,s1 b1 and c4 ,outside the main steles is the narrow cortex ,r and portions of leaf-bases ,i-,,iv4 ,the lowest section1 ,c1 shows part of a peripheral snake-ring with a slight swelling at f on its inner side which1 as seen in sections ,b and ,a1 foreshadows the separation of the star-ring ,s and the consequent break in the continuity of the snake-ring 7d1 e1 sect4 ,b74 ,in section ,a the gap is closed3 in the longitudinal section between ,b and ,a the star-ring ,s is seen to form two branches1 a and b1 the branch a closing the gap between d and e in section ,b4 ,these sections demonstrate the formation of a star-ring from the main peripheral stele and the formation of additional star-rings by branching4 ,illustration3 ,fig4 #dai4 ,medullosa ,leuckarti4 ,diagrammatic sketch of stem showing longitudinal and transverse sections3 for explanation see text4 7,after ,weber and ,sterzel47 ,numerous vascular bundles destined for the leaves are scattered in the cortex4 ,the course of the decurrent leaf-base ,i is shown on the longitudinal faces1 its boundary being marked by crowded stereome strands 7of the ,myeloxylon ,landrioti type72 other leaf-bases are represented by ,,ii1 ,,iii1 and ,,iv4 ,in habit ,medullosa ,leuckarti differs from such a type as ,m4 stellata in its relatively shorter and stouter stem and in the shorter internodes4 ,leaves and ,reproductive ,organs4 i4 ,leaves4 ,it has already been stated that in some cases petioles occur in organic connexion with ,medullosan stems1 notably in ,m4 anglica and ,m4 ,leuckarti3 in the exceptionally rich collection in the ,chemnitz ,museum1 which forms a fitting memorial of the work of the late ,prof4 ,sterzel1 there is a stem of ,m4 ,leuckarti bearing large petioles of the type known as ,myeloxylon radiatum4 ,the occurrence of vascular bundles in the cortex of other species of stem identical with those in the attached petioles points to a uniform type of leaf-structure so far as regards the petioles and rachises of ,medullosa4 ,while it is clearly unnecessary to distinguish by a special generic title the petrified portions of fronds known to belong to certain species of stems1 the frequent occurrence of detached petioles necessitates some distinctive term4 ,the name employed is ,myeloxylon3 the genus was instituted by ,brongniart in #ahdi for ,cotta's species ,medullosa elegans the petiolar nature of which was suspected by ,binney in #ahgb4 ,myeloxylon 7,medullosan leaf-stalks74 #ahcb4 ,medullosa elegans ,cotta4 #ahfe4 ,stenzelia ,goeppert4 #ahgf4 ,myelopteris ,renault#bgi2 #ahgg1 ,aulacopteris ,grand',eury#bhj4 ,there is a very close agreement in general anatomical structure between the numerous specimens of ,myeloxylon from the ,permian strata of ,saxony and ,france and the ,coal ,measures and ,millstone ,grit of ,england#bha2 the genus is also recorded from the ,upper ,carboniferous of ,kansas#bhb4 ,two well-defined types instituted by ,renault are1 however1 readily distinguished by the form of the hypodermal stereome strands4 ,myeloxylon may be defined as follows3 ,oval or cylindrical branched axes1 reaching a diameter of #ae cm41 bearing pinnae having the characters of ,alethopteris1 ,neuropteris1 ,odontopteris1 and some other genera that were formerly classed as ,ferns4 ,below a single-layered epidermis1 in which stomata have been recognised1 occur a few layers of parenchyma3 this superficial tissue1 which is rarely preserved1 is succeeded by a hypodermal region consisting of parenchymatous tissue and numerous vertical groups of narrow thick-walled fibres arranged as radial plates or circular1 oval1 or reniform strands 7the ,sparganum type of cortex74 ,in the hypoderm as in the ground-tissue generally secretory canals1 often accompanied by stereome1 are a characteristic feature4 ,the vascular system is represented by a considerable number of collateral bundles scattered through the ground-tissue and especially abundant in the outer region3 the bundles sometimes assume a more or less regular disposition in concentric circles4 ,each bundle consists of a small group of xylem tracheids1 for the most part spiral or scalariform1 though reticulately pitted elements are by no means rare1 with a single protoxylem group on the outer face next the phloem 7fig4 #dbj1 ,b1 ,c74 ,as a rule the xylem is wholly centripetal1 but occasionally the exarch structure becomes mesarch by the occurrence of a few centrifugal tracheids4 ,the phloem1 rarely preserved 7fig4 #dbj1 ,b71 consists of narrow sieve-tubes with parenchyma1 and the bundle as a whole is often partially enclosed by a sheath of fibres4 ,superficially the anatomical structure is similar to that of the petioles of ,angiopteris or ,marattia1 and both ,williamson#bhc and ,renault placed ,myeloxylon in the ,ferns2 but the collateral form of the vascular bundles1 the position of the protoxylem1 and the arrangement of the hypoderm tissues1 are cycadean features4 ,myeloxylon radiatum 7,renault74 ,illustration3 ,fig4 #dbj4 ,a1 ,b1 ,myeloxylon radiatum2 ,a1 petiole nat4 size2 ,b1 vascular bundle4 ,c1 ,myeloxylon sp4 vascular bundle2 px1 protoxylem4 ,d1 ,medullosa anglica2 section of pinnule4 7,a1 ,b1 after ,zeiller2 ,d1 after ,scott47 ,this type is characterised by the radially elongated stereome of the hypoderm4 ,prof4 ,zeiller#bhd1 who has given a very clear and concise description of ,myeloxylon1 is disposed to regard ,cotta's ,medullosa elegans as a specifically distinct form on the ground that there are two concentric zones of stereome in the hypoderm2 but this feature is shown only in one of ,cotta's figures1 and ,weber and ,sterzel#bhe point out that a doubting of the hypoderm zone may be caused by accidental juxtaposition of two faulted pieces of peripheral tissue4 ,the drawing reproduced in fig4 #dbj1 ,a1 shows the structural plan of an unusually large petiole from the ,permian of ,autun3 a portion of the outer tissue is seen in fig4 #dah1 ,a4 ,the vascular bundle1 fig4 #dbj1 ,c1 from a ,millstone ,grit specimen#bhf1 shows the centripetal nature of the xylem and fragments of phloem in the outer half of the bundle1 with imperfectly preserved fibres abutting on the xylem4 ,the characteristic hypoderm is shown also in fig4 #dah1 ,a2 the double xylem strand on the left illustrates a common feature caused by the branching of vascular bundles4 ,several secretory canals are scattered in the ground-tissue4 ,the pinnules of ,myeloxylon radiatum1 or at least of some specimens1 have been shown by ,renault to be of the ,neuropteris type4 ,myeloxylon ,landrioti 7,renault7#bhg4 ,in this species the distinguishing feature is the occurrence of the hypodermal stereome in the form of circular1 oval1 or reniform strands in place of the radial plates of ,m4 radiatum4 ,it is this form of petiole that was borne by the stems of ,medullosa anglica and ,m4 ,leuckarti4 ,in ,m4 anglica the pinnules 7fig4 #dbj1 ,d7 are of the ,alethopteris type1 almost certainly ,a4 lonchitica4 ,renault and ,zeiller have described ,french specimens of ,myeloxylon ,landrioti bearing pinnules like those of ,alethopteris aquilina and ,a4 ,grandini4 ,myeloxylon topekense 7,penhallow74 ,the occurrence of ,myeloxylon petioles in the ,new ,world was recorded by the late ,prof4 ,penhallow#bhh who founded this species on some imperfectly petrified specimens from ,upper ,carboniferous strata at ,topeka1 ,kansas4 ,enough material was available to show the ,myeloxylon characters1 but the preservation is too imperfect to admit of a complete diagnosis4 ,the hypodermal stereome shows a tendency to form tangentially extended strands in place of the more circular or radially elongated groups in the ,european species4 ,in addition to ,alethopteris1 ,neuropteris 7including ,cyclopteris7 and ,odontopteris fronds1 which are known to possess rachises with the ,myeloxylon features1 there is reason to believe that the ,permian ,callipteris fronds and possibly some of the older ,taeniopteris leaves may also belong to ,medullosa#bhi4 ,it is1 however1 unsafe to assume that the occurrence of ,myeloxylon petioles necessarily denotes the existence of ,medullosa4 ,the ,french stem ,colpoxylon aeduense ,brongn4#bij bore leaves with the same general anatomical features as those of a typical ,myeloxylon1 and there can be little doubt that other genera of the ,medulloseae also possessed fronds constructed on the same plan as those known to have been borne by ,medullosa4 ,an interesting illustration of an injured organ that had produced a wound-cambium is afforded by a ,myeloxylon petiole from the ,coal ,measures described by ,mr ,holden#bia4 ,reproductive ,organs4 ,reference was made in volume ii4 to the reasons which led to the removal of several genera of ,carboniferous and ,permian fronds from the ,filicales to the ,pteridosperms1 and in ,chapter xxix4 of the present volume certain species of ,sphenopteris are described as the foliage of ,lyginopteris and ,heterangium4 ,it is with such genera as ,neuropteris1 ,alethopteris1 ,linopteris and others that we are now more especially concerned1 as they represent some of the types of leaves borne by ,medullosa and other members of the ,medulloseae4 ,the absence of any specimens among the large number of these common genera bearing undoubted sporangia aroused suspicion as to the correctness of the generally accepted view that these fern-like fossils were the leaves of ,palaeozoic ,ferns4 ,subsequently the suspicion based on negative evidence was confirmed by researches into the anatomical structure of the leaf-bases1 petioles1 and fragments of pinnae attached to and associated with stems of ,medullosa4 ,it is only in a few cases that actual organic connexion between reproductive organs and ,medullosan leaves has been demonstrated1 but from such facts as are established it is safe to make the general statement that stems of ,medullosa--a generic term that undoubtedly includes plants which1 had we a fuller knowledge of them as complete individuals1 would be assigned to more than one generic type--possessed fronds simulating in habit those of certain ,ferns with some of the pinnae bearing seeds often of considerable size and in all cases of complex structure1 agreeing in many respects with those of existing ,cycads1 while other fronds1 or in some cases it may be other pinnae1 bore microsporangia similar in form to the sporangia of ,ferns4 a4 ,microsporangia4 ,neuropteris4 ,a4 ,neuropteris heterophylla#bib4 ,several examples of supposed fertile specimens of ,neuropteris are recorded in palaeobotanical literature1 but it was not until #ahhg that any satisfactory specimen was discovered4 ,in that year ,kidston#bic described a specimen of ,neuropteris heterophylla from the ,lower ,coal ,measures of ,scotland in which slender forked branchlets bear small bodies at their tips some of which appear to represent four-valved organs 7fig4 #dba1 ,d71 though the imperfect state of preservation renders impossible any definite pronouncement as to their structure4 ,to the specimen are attached a few sterile pinnules1 showing that it is a portion of a frond of ,n4 heterophylla characterised by the substitution of reproductive organs for pinnules4 ,the subsequent discovery of seeds attached to pinnae of the same species afforded strong presumptive evidence1 almost amounting to proof1 of the microsporangial nature of the ,scotch specimen4 ,for this specimen1 although no precise diagnosis is possible1 ,dr ,p4 ,bertrand#bid has proposed the generic name ,neurotheca4 ,in #aiaa the ,abb ,carpentier#bie described some small ovoid bodies1 #a-ae mm4 long1 from the ,coal ,measures of ,france arranged in groups of #d to #f and in some cases said to be borne on a slender pedicel which he found in association with ,n4 heterophylla and compared with sporangia described by ,lesquereux from the ,coal ,measures of ,arkansas as ,sorocladus stellata#bif4 ,these supposed microsporangia have recently been assigned by ,bertrand#big to ,sphenophyllum4 ,illustration3 ,fig4 #dba4 ,a4 ,potoniea adiantiformis ,zeill4 7very slightly enlarged74 ,b4 ,microsporangia of ,potoniea 7enlarged74 ,c4 ,linopteris obliqua2 side-view of microsporophyll4 ,d4 ,neuropteris heterophylla1 pinnules and microsporangia 7874 ,e4 ,linopteris obliqua1 surface-view of microsporophyll4 7,a1 ,c1 ,e1 after ,p4 ,bertrand2 ,b1 after ,carpentier2 ,d1 after ,kidston47 ,b4 ,neuropteris gigantea1 etc4 ,potoniea1 ,zeiller4 ,in #ahii ,zeiller#bih instituted the name ,potoniea for some peculiar fertile leaves found in the ,coal ,measures of ,heraclea consisting of a branched axis with cuneate segments1 #g-aj #f-h mm41 bearing numerous fusiform bodies1 #a-ae mm4 long1 at the upper edge 7fig4 #dba1 ,a74 ,these marginal bodies he regarded as sporangia and expressed the opinion that ,potoniea may be the fructification of some form of ,neuropteris1 ,mariopteris or ,alethopteris4 ,carpentier#bii afterwards described similar though rather larger examples from the ,pas-de-,calais coal-field as microsporophyll fragments of some ,pteridosperm3 he stated that similar specimens had been found by ,kidston in ,england4 ,in a later work ,carpentier#cjj described the sporangia as crowded in groups 7fig4 #dba1 ,b7 in the substance of the thick lamina of ,potoniea1 and he connected the fertile segments with ,neuropteris gigantea1 ,n4 pseudogigantea ,pot4 and ,linopteris obliqua 7,bunb474 ,similar specimens are said to have been found in ,holland and ,silesia4 ,bertrand#cja also records the association of ,potoniea with ,neuropteris gigantea and ,n4 pseudogigantea3 he describes some specimens as belonging to ,n4 gigantea ,sternb4 while others1 distinguished only by small differences1 he attributes to ,n4 pseudogigantea4 ,kidston#cjb has recently drawn attention to the inconstancy of the characters mentioned by ,potoni as distinguishing features of ,n4 pseudogigantea1 and he shows good cause for referring the examples so named to ,n4 gigantea4 ,the fertile lamina is almost orbicular in surface-view and attached to a slightly excentric pedicel2 the microsporangia are borne on the lower surface and probably in groups as described by ,carpentier4 ,neuropteris ,carpentieri ,kidston4 ,kidston#cjc has recently described some fertile leaflets under this name from the ,westphalian series of ,south ,staffordshire which he identifies with ,french examples referred by ,carpentier#cjd to ,potoniea adiantiformis ,zeill4 ,the fertile pinnules are thick and sub-cyclopteroid in form2 the upper surface bears densely packed1 narrow and long1 microsporangia1 #d #je mm41 containing more or less spherical microspores #de-fj in diameter2 the ventral face of the lamina on the removal of the spores shows several strong veins4 ,with these are associated sterile pinnules of the ,neuropteroid type1 and examples are described intermediate between the sterile and fertile leaflets4 ,kidston believes the specimens to be microsporophylls of some species of ,neuropteris1 but as the material does not suffice for identification with any known species a new name is proposed4 ,it is pointed out that in some states of preservation the leaflets resemble ,goeppert's ,permian species ,dictyothalamus ,schrollianus#cje4 ,alethopteris4 ,linopteris4 ,no specimens of ,alethopteris fronds have so far been described that afford any information as to the nature of the microsporangia1 and we have no means of knowing whether they were borne on naked pedicels as in ,neuropteris heterophylla1 or on modified pinnules as in ,n4 gigantea4 ,zeiller in #ahhhcjf described some fertile pinnules of ,dictyopteris ,schtzii ,roem4 from ,commentry bearing two rows of long sporangia3 he subsequently transferred this species to the genus ,linopteris#cjg and expressed the opinion that the sporangia occur singly and not in groups as he originally believed4 ,zeiller compares the fertile pinnules with the type ,crossotheca4 ,bertrand#cjh1 as the result of examining similar specimens1 has suggested that the fringe of pendulous bodies regarded by ,zeiller as sporangia may be tooth-like lobes of modified pinnules which served to protect microsporangia borne on the lower surface of the lamina4 ,the nature of the impressions is not clear1 though there is little doubt that they are microsporophylls4 ,the fertile pinnae of ,linopteris obliqua 7,bunb47 described by ,carpentier#cji and ,bertrand#caj closely resemble the microspore-bearing organs which have been referred to ,neuropteris gigantea2 they have the characters of ,potoniea and consist of oval laminae similar to the sterile pinnules but about half their size3 the lamina was attached excentrically to a slender stalk 7fig4 #dba1 ,c1 ,e7 and traversed by numerous occasionally anastomosing veins4 ,no actual microsporangia have been discovered in organic connexion with the lamina4 b4 ,megasporangia4 ,neuropteris4 ,kidston's discovery of undoubted seeds attached to pinnae of ,neuropteris#caa marked an important step in our more exact knowledge of the morphology of ,medullosan sporophylls4 ,specimens from the ironstone balls 7,coal ,measures7 of ,coseley near ,dudley showed seeds attached to portions of pinnae bearing pinnules of ,neuropteris heterophylla4 ,the seeds are approximately #c cm4 long and from #aaj to #adj cm4 broad2 oblong and gradually tapering from the middle to a slightly curved and obtuse apical snout 7fig4 #dbb74 ,the outer surface shows numerous longitudinal ribs which no doubt represent hypodermal fibres4 ,the preservation of the seeds1 which appear to be circular in section1 is not such as to render possible a description of structural features4 ,in their asymmetrical form the seeds agree with the genus ,platyspermum as recently defined by ,arber1 but ,kidston's specimens are in all probability radiospermic4 ,kidston compares the ,neuropteris seeds with ,rhabdocarpus tunicatus as figured from the ,commentry coalfield#cab and with specimens from ,gard named by ,grand',eury ,r4 subtunicatus#cac4 ,illustration3 ,fig4 #dbb4 ,neuropterocarpus ,kidstoni 7,arber74 7,after ,kidston2 #c47 ,additional proof of the occurrence of seeds on ,neuropteris fronds is furnished by examples from the ,coal ,measures of ,holland described by ,kidston and ,jongmans#cad3 these seeds are of the same general type as those from ,coseley but nearly twice as large1 and they were borne at the tips of a dichotomously branched pedicel of ,neuropteris obliqua4 ,grand',eury in #aijdcae recorded the association of radiospermic seeds with ,neuropteris fronds though no case of actual attachment was found4 ,it is1 however1 noteworthy that he speaks of the frequent association with ,neuropteris of seeds characterised by six or rarely twelve longitudinal keels1 a feature recalling the sclerotesta of ,trigonocarpus and allied seeds4 ,until petrified specimens are available it is impossible to refer the seeds of ,neuropteris to a generic type founded on structural features3 the seeds described by ,kidston are1 as he says1 very similar in external characters to species assigned to ,rhabdocarpus1 and there can be little doubt as to the generic identity of the ,neuropteris seeds and some of the impressions referred to ,rhabdocarpus which are characterised by a similarity in form1 an apical snout that gives an asymmetrical appearance to the specimens and the presence of numerous longitudinal striations#caf4 ,it is1 however1 by no means certain that these seeds possessed the morphological features of ,rhabdocarpus as described by ,brongniart in petrified examples from ,st tienne#cag4 ,the seeds of ,neuropteris may1 as ,kidston suggests1 agree anatomically more closely with ,pachytesta#cah1 a type that ,grand',eury associates with ,alethopteris fronds4 ,with a view to avoid the danger of incorrectly identifying petrified specimens and impressions that cannot be proved to belong to the same generic type1 ,i have suggested the restriction of the name ,rhabdocarpus#cai to seeds that do not furnish evidence as to internal structure1 and the employment of the designation ,rhabdospermum for seeds that conform to those described by ,brongniart as ,rhabdocarpus4 ,the seeds of ,neuropteris may be of the ,rhabdospermum type or they may agree anatomically more closely with ,trigonocarpus or ,pachytesta2 they are members of either the ,trigonocarpales or the ,cardiocarpales1 probably the former group4 ,dr ,p4 ,bertrand#cbj assigns to ,neuropteris gigantea some seeds of the ,hexapterospermum 7 ,hexagonocarpus#cba7 type which occur in association with cupule-like organs4 ,these supposed cupules resemble the ,potoniea leaflets with microsporangia also referred to the same species of ,neuropteris2 they are characterised by a laciniate edge and may be compared with the ,indian fossil described by ,zeiller as ,ottokaria bengalensis#cbb 7fig4 #dcc74 ,dr ,arber#cbc and ,dr ,p4 ,bertrand#cbd have independently proposed the generic name ,neurospermum for the seeds of ,neuropteris heterophylla and ,n4 obliqua in preference to ,rhabdocarpus3 the former author speaks of the seeds of ,n4 heterophylla as ,neurospermum ,kidstoni4 ,the generic term ,neuropterocarpus used by ,grand',eury in #aijdcbe1 though not defined by him1 has priority and avoids the adoption of a new designation for seeds attached to ,neuropteris fronds4 ,in his definition of ,neurospermum ,arber makes no reference to the obliquity of the apical snout that is clearly shown in fig4 #dbb4 ,there is no evidence that ,neuropterocarpus possessed a cupular investment comparable with that of ,lagenostoma4 ,additional instances of the association of seeds with ,neuropteris fronds are recorded by ,renier from the ,belgian ,coal ,measures1 also by ,bertrand and ,chodat from ,france3 ,renier found seeds associated with ,n4 ,schlehani ,stur and with the same species of frond ,bertrand found impressions of oval ribbed seeds4 ,prof4 ,chodat#cbf has figured some fragments of ,neuropteris pinnules referred to ,n4 auriculata ,brongn4 from the ,stephanian of ,france which show small seed-like bodies apparently in organic connexion with the lamina2 but the specimens are too imperfect to afford any satisfactory evidence as to the nature of the reproductive organs4 ,lotsy#cbg has expressed the opinion that the bodies attached to ,neuropteris pinnae described by ,kidston and other authors as seeds may possibly be vegetative buds1 but if this were the case one would expect to find some evidence of the bud-nature in some at least of the specimens that have already been found4 ,it would seem that the microsporophylls of ,neuropteris were constructed on different plans1 some being of the type described by ,zeiller and other observers as ,potoniea1 while others bore sporangia on pinnae without any accompanying laminae2 but our knowledge of the latter form represented by ,kidston's specimen of ,neuropteris heterophylla 7fig4 #dba1 ,d7 is very incomplete4 ,on the other hand the seeds appear to have been characterised by features suggesting a close affinity to ,trigonocarpus and pointing to membership of the same family4 ,alethopteris4 ,although no specimens have been discovered showing actual connexion between fronds and seeds1 it is practically certain that ,alethopteris leaves1 or at least some species of the genus1 bore seeds of the ,trigonocarpus type4 ,the association of ,trigonocarpus ,parkinsoni with ,alethopteris lonchitica is too frequent to be fortuitous and there is further evidence afforded by certain anatomical resemblances4 ,in ,france other species of ,alethopteris1 e4g4 ,alethopteris ,serlii and ,a4 ,grandini1 occur in association with ,pachytesta#cbh1 a large seed similar to ,trigonocarpus1 and ,trigonocarpus is found in the ,pas-de-,calais coal-field with ,alethopteris ,serlii4 ,,trigonocarpus4 ,brongniart4 ,the generic name ,trigonocarpum was instituted by ,brongniart in #ahbhcbi for ovoid longitudinally ribbed #8fruits' from ,upper ,carboniferous strata1 the type-species being named ,t4 ,parkinsoni4 ,the generic name is often altered to ,trigonocarpon3 ,williamson#ccj1 who adopted this form1 states that ,brongniart substituted ,trigonocarpon for ,trigonocarpum in his ,tableau#cca1 but in that work the original termination is used1 the form ,trigonocarpon1 probably the result of a slip1 appearing only in the index4 ,in his later work on seeds ,brongniart adopted the name ,trigonocarpus1 and in recent years this has been widely employed4 ,among other species named by ,brongniart are two previously referred by ,sternberg to ,palmacites4 ,several examples of ,brongniart's genus were described by ,lindley and ,hutton1 and in their description of ,t4 ,noeggerathii the statement is made that a fractured specimen demonstrated that #8the fossil in its ordinary state is an interior part divested of fleshy covering'#ccb2 this suspicion of the true nature of the nut-like fossils was afterwards proved correct by the investigations of ,hooker and ,binney#ccc and by the later work of ,williamson4 ,the specimens on which the genus was founded are casts of seed-cavities and it is in this state that the seeds are usually preserved1 often in large numbers1 in the sandstones of the ,coal ,measures1 as in the block shown in fig4 #dbc from the famous quarry at ,peel near ,bolton1 ,lancashire4 ,another type of preservation is represented by the seeds figured by ,lindley and ,hutton as ,carpolithes alata#ccd1 but the generic identity of the two states was not recognised until the discovery of petrified material afforded the clue4 ,figs4 #dbd1 #a1 #dbe illustrate the appearance of ,trigonocarpus when preserved as a carbonised impression showing a thick fleshy envelope enclosing an oval kernel with a hard wall prolonged upwards as a longer or shorter micropyle4 ,casts of the seed-cavity are represented in figs4 #dbc2 #dbd1 #b1 #c4 ,the surface of these casts occasionally shows one or more short cylindrical projections which are probably extensions of the sand or mud into holes formed in the testa by boring insects4 ,the view that ,trigonocarpus seeds are #8obviously ,palm fruits' was not accepted by ,hooker and ,binney who inclined to regard them as the seeds of ,conifers and compared them especially with the similar nuts of ,ginkgo seeds 7cf4 fig4 #fca1 ,c74 ,it was ,mr ,wild#cce who was first struck by the association of ,trigonocarpus and the petioles of ,medullosa 7,myeloxylon7 and by some resemblances in structure between the testa and the hypoderm of the petioles2 though1 as ,scott and ,maslen#ccf point out1 the agreement is not so close as ,wild believed1 his view of a possible connexion between the reproductive and vegetative organs has been confirmed4 ,williamson extended our knowledge of the genus by his account of ,trigonocarpus olivaeformis ,lind4 and ,hutt41 a form that is specifically identical with ,t4 ,parkinsoni ,brongn4 ,this author also drew attention to the close resemblance between ,brongniart's three genera ,trigonocarpus1 ,hexapterospermum1 ,tripterospermum and expressed doubts as to the possibility of founding specific differences on casts of the ,trigonocarpus type without the evidence of anatomy4 ,our knowledge of the structure of ,trigonocarpus has in recent years been considerably extended by the researches of ,oliver1 ,scott and ,maslen1 and ,salisbury4 ,illustration3 ,fig4 #dbc4 ,casts of the seed-cavity of ,trigonocarpus ,parkinsoni4 7,manchester ,museum4 nat4 size47 ,trigonocarpus ,parkinsoni#ccg ,brongniart4 ,the seeds of this species like all examples of the genus are radiospermic1 that is radially symmetrical in contrast to the flattened or platyspermic seeds4 ,the complete seed is elongate oval in form when preserved as an impression 7fig4 #dbe1 ,a7 and reaches a length of #d-e cm43 the casts of the seed-cavity are ovoid and provided with three prominent ridges 7fig4 #dbd1 #b1 #c74 ,the testa forms a thick covering differentiated into three regions1 an outer flesh or sarcotesta1 a sclerous shell or sclerotesta1 and an inner flesh4 ,transverse sections show that the sclerotesta has three sharp longitudinal keels with corresponding furrows on the inner face1 and between each pair of main ribs are #b-c less prominent ridges1 usually #ab in all 7fig4 #dbf74 ,the sarcotesta consists of thin-walled parenchyma passing externally into a more lacunar tissue with a palisade-like hypoderm3 the sclerotesta consists of thick cells which interlace and form an efficient protective shell4 ,both the sarcotesta and sclerotesta are continued into the apical region as the wall of the long micropyle1 the sarcotesta being prolonged beyond the sclerotesta at the apex of the integument#cch4 ,the micropyle is triangular in section and may exceed in length the whole seed 7figs4 #dbe2 #dbf1 ,a74 ,its form as seen in transverse section 7fig4 #dbf1 ,b7 suggests the presence of wings3 this appearance may be deceptive and due to pressure or1 more probably1 it represents an original feature4 ,the seed-body1 that is the portion enclosed by the integument1 consists of the nucellus1 represented by a few crushed layers of cells1 bounded by a well-defined epidermis2 the nucellus is separated from the integument from the base of the seed upwards1 an important feature in which this and some other ,palaeozoic seeds differ from ,lagenostoma and the seeds of recent ,cycads which are characterised by an integument adnate to the nucellus up to the level of the shoulder2 the seeds of the ,conifer ,phyllocladus afford an example of separation of integument and nucellus as in ,trigonocarpus4 ,the innermost layer of the nucellus consists mainly of tracheal tissue investing the large megaspore 7fig4 #dbf1 ,a1 ,c1 m7 which is preserved as a contracted membrane detached from the nucellus after the death of the seed4 ,at the summit of the nucellus is a relatively small pollen-chamber 7fig4 #dbf1 ,a1 ,pc7 like a broad and low cupola bearing a terminal beak which extended some distance into the micropylar tube4 ,no microspores have been found in this species1 but ,oliver#cci records the occurrence of multicellular microspores in ,trigonocarpus pusillus4 ,the pedicel of the seed had a central strand of sclerous tissue penetrated by a concentric vascular bundle which gives off six strands to supply the sarcotesta 7fig4 #dbf1 ,c1 v7 and then passes into the nucellus where it forms a tracheal sheath 7fig4 #dbf1 ,a1 nt7 surrounding the lower part of the megaspore and at a higher level breaks up into anastomosing strands of tracheids which reach up to the plane of insertion of the pollen-chamber4 ,illustration3 ,fig4 #dbd4 ,trigonocarpus4 #a4 ,section of imperfect seed showing a micropyle2 b1 sclerotesta2 c1 cast of seed-cavity2 #b1 #c1 apical and basal view of seed-cast4 7,approximately nat4 size47 ,m4 ,s4 ,illustration3 ,fig4 #dbe4 ,trigonocarpus ,parkinsoni4 ,a4 ,impression showing the nucule and sarcotesta4 7 ,carpolithes alata ,lind4 and ,hutt47 ,b4 ,specimen with long micropyle4 7,a1 nat4 size2 from the ,lower ,coal ,measures of ,kilmarnock2 ,b1 nat4 size2 ,middle ,c4 ,m4 of ,yorkshire4 ,kidston ,coll41 #aegi and #ajfb47 ,illustration3 ,fig4 #dbf4 ,trigonocarpus ,parkinsoni4 ,a1 longitudinal section2 ,sa1 ,sc1 if1 sarcotesta1 sclerotesta1 inner flesh2 mi1 micropyle2 ,pc1 pollen-chamber2 v1 vascular bundles2 m1 megaspore and prothallus2 t1 tracheal disc2 nt1 tracheids in the nucellus4 ,b1 transverse section of the upper region showing the sarcotesta1 sclerotesta 7black7 and the micropyle4 ,c1 transverse section of ,t4 ,parkinsoni4 ,d1 transverse section of ,trigonocarpus shorensis4 7,a1 ,c1 after ,scott2 ,b1 after ,wild2 ,d1 after ,salisbury47 ,a second species described by ,scott and ,maslen as ,trigonocarpus ,oliveri has been further investigated by ,salisbury who finds that it is an #h-;angled seed which cannot be retained in the genus ,trigonocarpus3 its systematic position #8must for the present remain uncertain#cdj4' ,dr ,arber has recently described a new species of ,trigonocarpus1 ,t4 ,moyseyi#cda1 from the ,nottingham ,coal-field 7,middle ,coal ,measures71 similar to ,t4 ,parkinsoni but much broader in proportion to its length3 this species is founded on an impression without structure4 ,the species ,trigonocarpus ,dawesi ,lind4 and ,hutt4#cdb1 from the ,middle ,coal ,measures of ,lancashire1 was founded on casts differing in their large dimensions from those of ,t4 ,parkinsoni3 specimens referred to this species were described by ,fiedler#cdc from ,saxony in #aheg and ,lesquereux#cdd figures similar casts from the ,upper ,carboniferous and ,permian rocks of ,north ,america4 ,trigonocarpus shorensis ,salisbury4 ,this species1 founded on specimens from the ,lower ,coal ,measures of ,shore1 ,lancashire#cde1 may exceed #d cm4 in length and has a breadth of #be cm4 ,in general plan it agrees with ,t4 ,parkinsoni but there are certain well-marked differences3 the micropyle is much shorter2 the thick sarcotesta1 attaining a breadth of #f mm4 at the base of the micropyle1 is characterised by the presence of six peripherally placed vascular bundles 7fig4 #dbf1 ,d1 v7 in contrast to the deeply embedded bundles of ,t4 ,parkinsoni4 ,below the epidermis of the sarcotesta is a hypoderm formed of radially disposed plates of sclerous tissue similar to that of ,myeloxylon and different from the palisade-like hypoderm of the type-species4 ,within the sarcotesta is a hard shell1 the sclerotesta1 characterised by three prominent ribs extending from base to apex and three shorter ribs which reach from the chalaza to about a third of the length of the seed4 ,the fact that the sarcotesta and sclerotesta pass gradually into one another is a point in favour of the view that the integument is a single structure4 ,there appears to be good evidence of the restriction of an inner flesh to the micropylar region1 whereas this tissue in ,t4 ,parkinsoni was probably continuous over the whole inner face of the sclerotesta4 ,the sarcotesta is lacunar in its outer part as in some other types of ,palaeozoic seeds1 a feature probably connected with floating efficiency4 ,trigonocarpus shorensis occurs in association with ,myeloxylon petioles1 and there is a resemblance between the seed and the vegetative organs in the structure of the hypoderm as also in the structure of the secretory sacs which are particularly numerous in this species4 ,salisbury draws attention to the close resemblance between the form of ,t4 shorensis and the seeds found in organic connexion with pinnae of ,neuropteris obliqua#cdf4 ,the species ,t4 corrugatus described by ,renault#cdg bears a close resemblance to ,t4 shorensis4 ,other ,genera founded in part on ,reproductive ,organs which may belong to the ,medulloseae4 ,codonotheca1 ,schtzia1 ,whittleseya1 ,dolerophyllum1 ,ottokaria1 ,strobilites4 ,,codonotheca4 ,sellards4 ,codonotheca caduca ,sellards4 ,this genus was founded on some spore-bearing bodies from the ,coal ,measures of ,illinois#cdh3 nothing is known as to the plant which bore them1 but ,sellards is inclined to associate them with ,neuropteris decipiens ,lesq4#cdi1 a species abundant in the same coal-field4 ,whatever may have been the parent-plant it is probable1 as the author of the genus believes1 that ,codonotheca is the microspore-bearing organ of a ,pteridosperm4 ,as shown in fig4 #dbg1 #e1 the form is that of a stalked cup consisting in the basal portion of a stout axis1 the peripheral tissue of which is believed to have been fleshy1 containing an axial rod of conducting tissue running up to the floor of the cup1 c1 and then dividing into six vascular strands1 each of which forks into two branches4 ,the upper part is composed of six linear segments united basally to form the sloping surface of the cup4 ,on the inner face of each segment is a more or less well-defined depression covered with large elliptical spores #bi-ca mm4 long by #ah-ai mm4 broad 7fig4 #dbg1 #f1 #h74 ,the presence of a median ridge 7fig4 #dbg1 #h7 indicates a bilateral origin4 #8,there is no grouping of the spores or other indication of the location of the sporangia1 which were doubtless more or less completely immersed in the tissue1 the dividing wall disappearing at maturity4' ,the spores are seen in fig4 #dbg1 #b1 #c1 on the inner face of the lobes4 ,some of the specimens have a fairly long pedicel3 in the example shown in fig4 #dbg1 #a1 the fleshy part of the basal portion is not preserved1 only the more resistant vascular core4 ,in a later account of these organs ,sellards speaks of several lying by the side of a central stalk to which he thinks they were originally attached by slender pedicels4 ,in view of ,dr ,benson's interpretation of the morphology of ,telangium it is permissible to suggest that if a central sporangium in such a synangium as that of ,codonotheca developed a megaspore and the peripheral sporogenous lobes were sterilised1 the result would be an arrangement not unlike the apical region of the seed ,physostoma1 the tentacles of which have been homologised with the canopy of ,lagenostoma4 ,there are obvious difficulties in the way of this1 perhaps strained1 comparison3 the larger size of the spore-bearing linear segments of ,codonotheca led ,sellards to regard each as a synangium rather than a single sporangium4 ,but precise information as to the structure of the ,american fossils is not as yet available4 ,if the association of ,codonotheca with ,neuropteris fronds has any significance it would favour a reference of these organs to the ,medulloseae4 ,in the absence of anatomical data it is impossible in some cases to distinguish microspore-bearing organs of the ,codonotheca type from small seeds enclosed in a lobed cupule or even seeds with a lobed integument3 a case in point is the ,new ,brunswick species ,pterispermostrobus bifurcatus ,stopes#cej4 ,illustration3 ,fig4 #dbg4 ,codonotheca caduca4 #a4 ,the vascular tissue preserved as a conical base which was originally surrounded by fleshy tissue 7cf4 #e72 ,i-,,iii1 ,,vi1 vascular bundles 7 #b74 #b1 #c4 ,segments with spores2 c1 floor of cup 7nat4 size74 #d4 ,vascular tissue as a cone in the middle of the fleshy base 7nat4 size74 #e4 ,plan of the whole organ opened out flat 7nat4 size74 #f4 ,spores 7 #bh74 #h4 ,a single spore showing median slit 7 #hd74 7,after ,sellards47 ,a ,spitzbergen1 ,culm1 fossil recently described by ,nathorst#cea as ,codonotheca 787 pusilla is briefly referred to under the genus ,pterispermostrobus4 ,,sch,,tzia4 ,geinitz4 ,this generic name was instituted by ,geinitz#ceb for some ,permian fossils obtained by ,bergmeister ,schtz and regarded by the author of the genus as probably fertile branches of some ,conifer4 ,a more complete account was published by ,goeppert#cec in his #8,permian ,flora1' where the name ,anthodiopsis ,beinertiana occurs on the ,plates1 printed before the publication of ,geinitz's description1 but in the text the specimens are referred to ,schtzia anomala4 ,schtzia anomala ,geinitz4 ,the type-species1 recorded from ,bohemia and ,silesia1 is represented by fertile shoots consisting of a thick main axis bearing apparently two-ranked though probably spirally disposed short lateral branches1 each of which terminates in a receptacle with numerous crowded linear-lanceolate bracts superficially resembling a partially expanded inflorescence of a ,composite4 ,goeppert believed that the branches bore seeds and he refers to this species a number of detached1 longitudinally striated and bluntly terminated1 seeds4 ,the same author describes other specimens from the same localities associated with ,schtzia anomala1 which he names ,dictyothalamus ,schrollianus#ced3 in habit these agree closely with ,schtzia but the receptacles1 the reticulate appearance of which suggested the generic name ,dictyothalamus1 bear a large number of small bodies regarded as seeds4 ,the preservation of the fossils is not such as to enable us to determine their true nature but it is probable that ,schtzia and ,dictyothalamus are not generically distinct4 ,in his description of ,dictyothalamus ,goeppert suggests that the two associated types may be the male and female shoots of one plant1 but he speaks of seeds in both cases4 ,schimper#cee1 who unites ,dictyothalamus with ,schtzia1 regards the latter as female and the former as male4 ,schtzia ,bennieana ,kidston4 ,this species1 described by ,kidston#cef from the ,calciferous series of ,scotland1 differs from ,s4 anomala in its much more slender axis and in the relatively narrower and less globular clusters of bract-like appendages4 ,the principal axis bears three lateral branches with terminal clusters of acute and narrow linear scale-leaves4 ,no seeds were found in association with the specimens4 ,schtzia permiensis 7,renault74 ,renault founded this ,permian species as ,antholithus permiensis#ceg on a specimen from ,lodve2 it consists of an incomplete inflorescence #fd cm4 long bearing four lateral branches with stalks #ae to #b cm4 long terminated by clusters of small oval bracts #e mm4 long4 ,renault compares the fossil with the recent ,conifers ,glyptostrobus and ,tsuga1 but it exhibits a much closer resemblance to ,schtzia anomala4 ,the genus ,schtzia1 originally described from ,permian strata1 is recorded also from ,westphalian strata in ,north ,africa#ceh as well as from ,lower ,carboniferous rocks in ,scotland4 ,the data at present available are insufficient to determine the morphological nature of the fertile branches3 the evidence adduced by ,goeppert in support of the occurrence of seeds is not convincing and the interpretation of the bract-like appendages is still an open question2 they may have formed a cupular investment to seeds1 but in the ,scotch species the general appearance rather suggests that they may be microspore-bearing organs comparable with those of ,codonotheca#cei4 ,there are no adequate grounds for supposing ,schtzia to belong to the ,coniferales1 a view advanced by some authors2 it is much more likely to represent the fertile shoots of a ,pteridosperm4 ,,whittleseya4 ,newberry4 ,the genus ,whittleseya1 referred by many authors to the ,ginkgoales1 has no substantial claim to be regarded as allied to that group3 its position is still uncertain1 but the recent discovery of fertile specimens suggests the probability of a relationship to ,potoniea and an identification of ,whittleseya as another form of microsporophyll of a ,pteridosperm4 ,illustration3 ,fig4 #dbh4 ,a1 ,c4 ,whittleseya elegans4 ,a1 single leaflet1 from ,pennsylvania4 7,after ,lesquereux2 nat4 size47 ,c1 diagrammatic sketch of part of a leaflet showing the teeth1 the striated texture of the carbonised layer1 and the vein-like markings on a lower surface4 7,after ,thomas2 enlarged47 ,b4 ,whittleseya brevifolia4 7,after ,white2 the smaller figure nat4 size47 ,the generic name was given by ,newberry#cfj to some leaves1 or possibly leaflets1 originally described by ,c4 ,whittlesey from the ,coal ,measures of ,ohio4 ,whittleseya is represented by species from several ,north ,american localities#cfa in ,ohio1 ,pennsylvania1 ,arkansas1 ,nova ,scotia1 and ,new ,brunswick#cfb2 it occurs in ,silesia and has recently been found in the ,english ,coal ,measures#cfc4 ,the genus is confined to ,upper ,carboniferous strata4 ,the leaves are fairly thick2 the lamina is oblong1 cuneate1 broadly triangular or linear1 usually rounded and truncate 7fig4 #dbh1 ,a1 ,c71 generally dentate at the distal end1 the proximal portion being gradually or abruptly contracted and occasionally prolonged into a short pedicel4 ,the veins or ribs are parallel to the sides of the lamina and except near the base unbranched4 ,whittleseya elegans ,newberry4 ,the type-species1 from ,north ,america and ,europe1 is characterised by its shovel-like lamina from #c to #f cm4 long closely resembling in shape some lepidopterous scales2 the surface is ribbed1 each rib corresponding to a tooth on the distal margin2 on each of the parallel ridges are #d-e longitudinal lines indicating either veins or stereome strands 7fig4 #dbh1 ,a1 ,c74 ,the examination of preparations made by ,dr ,kidston from a leaflet of this species enables me to add a few facts with regard to the microspores4 ,the spores1 which cover almost the whole surface of the lamina1 show a tendency to a more or less definite arrangement in longitudinal rows4 ,two types of cuticularised membrane are represented among the associated fragments3 in some pieces of cuticle the cells are short and have straight walls while in others the preservation is inferior and the cells appear to be longer and narrower4 ,one or both of these membranes probably belong to the sporangia4 ,the oval slit1 which is a striking feature on several of the spores 7fig4 #dbi71 points to their bilateral nature and dehiscence along the major axis4 ,a comparison of these spores with those obtained by ,kidston from the ,english species ,whittleseya fertilis reveals a very close agreement both in size and shape and confirms the identification of the ,staffordshire specimens as leaflets of ,whittleseya4 ,the large size of the microspores and the gaping oval aperture in some of them are features in which they agree closely with the spores of ,dolerophyllum fertile described by ,renault#cfd4 ,in both cases the spores tend to be arranged in long groups and they are practically identical in form and in the nature of the exine2 those of ,dolerophyllum are #bhj long while those of ,w4 fertilis reach a length of #bbj4 ,in some of the ,whittleseya spores the exine has split as in the specimen shown in fig4 #dbi1 but in others there are two curved lines along which dehiscence has begun1 a character in which the spores appear to be identical with those of ,dolerophyllum described by ,renault who speaks of dehiscence by means of an operculum4 ,there is1 ,i venture to think1 little doubt as to the very close affinity of the two types4 ,the systematic position of ,dolerophyllum is not certainly established2 if the generic identity of the leaves described as ,d4 ,berthieri ,ren4 and the petrified specimens named ,d4 fertile is assumed1 it is a legitimate inference that the genus is founded on fertile pinnules of a ,pteridosperm with foliage of the ,neuropteris or ,cyclopteris form4 ,it would seem probable that both ,whittleseya and ,dolerophyllum fertile are microspore-bearing leaflets of ,pteridosperms1 possibly of some ,medullosan plants4 ,the leaflets of ,whittleseya agree in form fairly closely with those of ,potoniea adiantiformis ,zeill4 described on a previous page#cfe as the male organs of a ,pteridosperm4 ,illustration3 ,fig4 #dbi4 ,microspores of ,whittleseya elegans4 ,a1 a group of spores2 ,b1 a single spore4 7,preparations made from an ,american specimen1 ,no4 #bcad1 in ,dr ,kidston's ,collection47 ,the specimens described by ,lesquereux from ,pennsylvania as ,w4 integrifolia and ,w4 undulata are less satisfactory than ,w4 elegans4 ,the ,arkansas species ,w4 microphylla#cff1 characterised by the obcuneate form of the lamina1 is said to occur not only as detached leaflets but in loose bunches at the ends of slender axes1 a circumstance favourable to the suggestion1 based on the recently described ,english specimens1 that the ,whittleseya leaves may be fertile pinnules of a ,pteridosperm frond4 ,among other species attributed to ,newberry's genus is ,w4 brevifolia ,wh4 from ,nova ,scotia#cfg with much smaller broadly triangular leaves #g mm4 long exclusive of the petiole and #h mm4 broad at the distal end 7fig4 #dbh1 ,b74 ,dr ,matthew#cfh has also described a ,canadian species ,w4 concinna from ,new ,brunswick in beds assigned by ,dr ,stopes#cfi to the ,westphalian series4 ,whittleseya fertilis ,kidston4 ,since the discovery of ,whittleseya elegans in the ,coal ,measures of ,staffordshire recorded by ,mr ,thomas1 ,dr ,kidston has published an account of some specimens from the same district under the name ,whittleseya 787 fertilis#cgj3 these consist of smaller cuneate scale-leaves or leaflets #ad-bd cm4 long and #h-i mm4 broad2 the lamina has a dentate upper margin and is longitudinally ribbed4 ,the scales occur in superposed pairs1 closely fitting but not organically connected1 at least in the state in which they are preserved2 each pair forms a sporangium-like case enclosing numerous spores but the actual sporangia or synangia have not been preserved4 ,kidston describes the spores as #baj-bbb in length1 elliptical1 and characterised in many cases by an oval slit2 they are practically identical with the microspores of ,w4 elegans4 ,,dolerophyllum4 ,saporta4 ,this name was proposed#cga primarily for a large ovoid petrified bud composed of rolled ,cyclopteroid leaves from ,permian rocks in the ,ural ,mountains1 which had been previously described by more than one writer under different names and regarded as a young shoot of a ,palm or other ,monocotyledon4 ,eichwald#cgb1 who published good drawings1 called the fossil ,noeggerathia ,goepperti4 ,saporta connected with this species some leaf-impressions from the ,permian of ,bohemia described by ,goeppert#cgc as ,noeggerathia cyclopteroides3 in his family ,dolerophylleae#cgd the ,french author included other leaves which are probably not closely related to the type-species1 ,dolerophyllum ,goepperti4 ,the ,dolerophylleae are spoken of by ,saporta and ,marion#cge as ,progymnosperms4 ,before the publication of ,saporta's note ,grand',eury had instituted the genus ,doleropteris#cgf and the family ,doleropteroideae2 in the former he included several forms of leaves agreeing generally with ,goeppert's ,noeggerathia cyclopteroides4 ,zeiller#cgg adopts ,grand',eury's designation for the ,russian fossil in preference to ,dolerophyllum1 a choice justified by considerations of priority2 but the latter name is retained in this account as it was assigned by ,saporta to the specimen of greatest botanical interest1 namely ,dolerophyllum ,goepperti1 and because it does not suggest affinity to ,ferns4 ,dolerophyllum ,goepperti 7,eichwald74 ,the type-species is from the ,zechstein of ,orenburg in the ,urals and no specimens having precisely the same structure have been found elsewhere4 ,eichwald assigned it1 with leaf-impressions of various kinds1 to the ,noeggerathieae and named it ,noeggerathia ,goepperti3 it had previously been described by ,kutorga#cgh as ,aroides crassispatha and ,unger#cgi included it among the ,palms as ,palaeospathe aroidea4 ,the species has been described also by ,saporta and ,marion and by ,renault#chj4 ,the following account is based on sections cut from a specimen in the ,british ,museum#cha which1 though assigned on the label 7within a query7 to ,france and named ,dolerophyllum ,berthieri1 is undoubtedly ,eichwald's species from ,east ,russia4 ,illustration3 ,fig4 #dcj4 ,dolerophyllum ,goepperti4 ,bud in surface-view1 ,a2 in longitudinal section1 ,b1 ,c2 in transverse section1 ,d4 7,british ,museum2 ,a1 nat4 size47 ,the specimen 7fig4 #dcj7 is #i cm4 long and #db cm4 broad3 at the slightly contracted and broken base is a piece of immature axis 7fig4 #dcj1 ,b1 a7 #ab mm4 in diameter overtopped by a mass of closely packed leaves encircling one another like the bulb-scales of an ,onion 7fig4 #dcj ,a1 ,c7#chb4 ,most of the leaves included in the bud were attached to the axis below the broken base4 ,the curved1 dichotomously branched1 veins are seen on some of the pieces of lamina on the surface of the bud 7fig4 #dcj1 ,a74 ,the considerable breadth of the leaves is demonstrated by the longitudinal and transverse sections4 ,in fig4 ,c most of the laminae can be traced through the whole height of each of the steep-sided arches3 a few overlapping margins are seen in fig4 ,d4 ,the veins are for the most part imperfectly preserved and appear as clear spaces at regular intervals in the brown mesophyll4 ,the axis of the shoot consists of homogeneous parenchyma except near the sloping sides where narrow dark bands 7fig4 #dcj1 ,b1 a7 mark the position of desmogen-strands of thin-walled elongated elements representing an early stage in the development of vascular bundles some of which have already produced spiral tracheids4 ,short secretory cells accompany the immature conducting elements4 ,the lamina slightly exceeds #b mm4 in thickness in the broadest part3 the mesophyll is composed of large parenchymatous cells of elliptical or spherical form often loosely attached owing to the well-developed system of intercellular spaces4 ,the lower epidermis1 assuming that the outer face of the rolled leaves is the morphologically lower surface1 forms a uniform layer of palisade cells characterised by their free conical ends 7fig4 #dca1 ,a1 ,b1 e7 which in some oblique sections appear as sharply pointed papillae with almost filiform apices2 but while the cells were doubtless papillose like those of the epidermis of a velvety petal1 the pointed form is due in part to the greater distinctness of the dark contents as compared with the lighter cell-walls4 ,the upper epidermis is much less distinct2 it consists of smaller flattened cells with occasional stomata4 ,renault#chc figures a specimen with stomata in a better state of preservation4 ,the vascular bundles are rendered conspicuous by large secretory cells on the lower side1 in the larger veins in the form of an arc or irregular group 7fig4 #dcb1 ,a71 but in the finer veins as single cells 7fig4 #dca1 ,a1 ,b74 ,these sacs resemble the tannin cells accompanying the veins in a leaf of ,ginkgo 7cf4 fig4 #fca1 ,g74 ,the xylem-elements are of two kinds1 7i7 elongated spiral and scalariform conducting elements1 forming a vertical plate of a few rows in the larger veins 7figs4 #dca1 #dcb7 or a small compact group in the more slender veins 7fig4 #dac1 ,a1 ,b72 7ii7 much larger isodiametric cells with reticulate or spiral thickening resembling the transfusion-tracheids of ,conifers or1 perhaps more closely1 similar elements in the leaves of ,lepidodendron4 ,these short tracheids are especially abundant on the flanks of the conducting tracheids 7figs4 #dca1 t2 #dcb1 ,a1 t71 but they sometimes form a complete investment4 ,in the obliquely cut vein reproduced in fig4 #dca1 ,d1 the transfusion-tracheids are abundant3 a few are enlarged in fig4 #dca1 ,e4 ,in the smaller veins 7fig4 #dca1 ,a1 ,b7 they are represented by the larger elements1 t1 on the sides of the conducting strands4 ,the protoxylem lies close to the upper edge in the middle line 7px1 figs4 #dca1 ,a2 #dcb1 ,a72 it is difficult to determine its precise position1 but it would seem to be slightly internal1 the bundle being not quite endarch4 ,no phloem was recognised in the ,british ,museum specimen1 but it presumably occurred1 if present1 where the black patch is shown in fig4 #dcb1 ,a4 ,renault describes some phloem in sections which he examined4 ,illustration3 ,fig4 #dca4 ,dolerophyllum ,goepperti4 ,transverse sections of leaves4 e1 epidermis2 s1 secretory cells2 t1 transfusion-tracheids2 px1 protoxylem4 7,british ,museum47 ,the mesophyll next the upper surface is in most cases represented by spaces between the veins which give a crenulated outline to the parenchyma 7fig4 #dcj1 ,c1 ,d72 in some places the spaces contain remains of very loose and crowded cells suggesting the original presence of very lacunar tissue or possibly of thin-walled storage-cells4 ,the confinement of stomata to what is assumed to be the upper surface may1 as ,renault and others have suggested1 indicate leaves which floated on water1 an inference opposed to the view that the gaps in the mesophyll mark the position of water-tissue4 ,no specimens have been described which enable us to correlate with certainty mature leaves or foliage-shoots with the petrified bud4 ,it is1 however1 not improbable that the impression from ,mount ,pel near ,epinac named by ,renault ,dolerophyllum ,berthieri#chd may be correctly referred to the same genus4 ,the type-specimen consists of an axis1 whether a rachis of a compound leaf or a shoot with simple leaves cannot be determined1 bearing partially overlapping more or less orbicular leaves #ah-bj cm4 in diameter1 with a ,cyclopteris venation4 ,among other leaves of unknown affinity referred to the same genus attention is drawn to ,dolerophyllum pseudopeltatum 7,grand',eury7#che with an orbicular lamina reaching in some specimens #bb #ai cm4 ,specimens of ,dolerophyllum pseudopeltatum are figured by ,renault from the ,commentry coal-field#chf1 some of which reach a diameter of #ab cm4 ,the only ,british specimen of a leaflet of this type which ,i have seen is one in ,dr ,kidston's collection from the ,stephanian series1 ,glamorganshire4 ,it is probable that some at least of the impressions assigned to ,dolerophyllum or ,doleropteris would be more appropriately included in ,cyclopteris or ,cardiopteris and may have been borne on the axis of large ,pteridosperm fronds4 ,grand',eury#chg has also called attention to the difficulty of distinguishing the larger ,cyclopteris leaflets from ,dolerophyllum4 ,some of the ,cyclopteroid leaflets figured by ,roehl#chh on ,neuropteris fronds differ but slightly from those of ,d4 pseudopeltatum4 ,the shoot showing large leaf-scars figured by ,saporta and ,marion#chi as probably the axis of a ,dolerophyllum may well be a piece of ,cordaites4 ,illustration3 ,fig4 #dcb4 ,a4 ,dolerophyllum ,goepperti1 section of vein4 ,b4 ,dolerophyllum ,berthieri2 s1 microspores4 ,c4 ,dolerophyllum fertile4 ,d4 ,dolerophyllum fertile1 microspores4 7,after ,renault47 ,microsporophylls assigned to ,dolerophyllum4 ,certain problematical fossils found in association with the sterile leaves of ,dolerophyllum ,berthieri have been described by ,renault as the male organs of that species4 ,these are elliptical discs1 #f #e cm41 with an excentrically placed stalk3 embedded in a carbonised lamina are numerous rows of elliptical bodies1 #daj #bhj1 characterised by two curved longitudinal grooves on the surface and regarded by ,renault as pollen-grains4 ,the chains of these microspores radiate outwards from the neighbourhood of the stalk and cover most of the surface of the disc 7fig4 #dcb1 ,b74 ,some silicified pieces of similar spore-bearing discs from ,grand' ,croix named ,dolerophyllum fertile#cij afford additional information as to these remarkable reproductive organs4 ,the earlier account of this species by ,renault is confirmed by ,solms-,laubach#cia who examined the original sections4 ,the peltate fleshy discs preserved as incomplete specimens consist of lacunar parenchyma #ae-ah mm4 thick traversed at right angles to the surface by numerous loculi 7fig4 #dcb1 ,c71 circular or oval in transverse section1 containing large numbers of microspores1 s1 similar in size and form to those on the carbonised discs of the ,mt ,pel specimen4 ,vascular strands occur between and parallel to the spore-chambers4 ,the spores contain #h-aj cells 7fig4 #dcb1 ,d7 and ,renault believes that dehiscence of the exine occurred along the two deep grooves which mark the limits of an operculum4 ,he emphasises the peculiar structure of the microspores by speaking of them as prepollinia3 in size and in the presence of internal cells 78 male prothallus7 they resemble the spores found in the pollen-chamber of a seed described by ,renault as ,aetheotesta elliptica#cib which he thinks may belong to a member of the ,dolerophylleae4 ,it has also been suggested that ,codonospermum may be a seed of ,dolerophyllum#cic4 ,an unconvincing specimen described by ,saporta and ,marion#cid as a seed-bearing bract is regarded by them as referable to ,dolerophyllum1 but the evidence for any connexion is far from satisfactory4 ,there is nothing definite to be said with regard to the affinity of ,dolerophyllum ,goepperti or the microsporophylls represented by ,d4 fertile and the specimens associated with ,d4 ,berthieri4 ,renault considers that both sterile and fertile specimens belong to the same genus1 which he assigns to a position between ,pteridophytes and ,cycads4 ,as ,solms-,laubach says1 the evidence supplied by the structure of the veins of ,d4 ,goepperti in favour of a cycadean alliance is not convincing4 ,the type of vernation is unlike that of any known ,cycad or indeed of any ,gymnosperm3 the large size of the leaves is another though weaker objection to this comparison1 as the pinnae of ,bowenia 7fig4 #cia7 and especially those of some species of ,zamia 7fig4 #chh71 are of equal or larger dimensions4 ,if1 as seems probable1 the xylem-strands are mesarch that is a point of contact with recent ,cycads1 but the bundle as a whole bears but a remote resemblance to that of a cycadean leaf and is much more like the veins of ,ginkgo4 ,the bud shown in fig4 #dcj1 ,a1 is probably a young shoot and not merely a large compound leaf4 ,if it were an unexpanded frond of ,neuropteris bearing ,cyclopteris pinnules we should expect to find indications of scattered desmogen-strands such as would occur in the ,myeloxylon type of rachis4 ,the resemblance to most forms of ,cordaites is by no means close though a few leaves referred to that genus 7e4g4 ,c4 circularis1 fig4 #dfh1 ,b7 are similar to those of ,dolerophyllum#cie4 ,the male organs are unlike those of any other plant3 they may be described as sporophylls with microsporangia or perhaps synangia embedded in the mesophyll and containing microspores similar to those of some ,pteridosperms or true ,gymnosperms4 ,attention has been called to the close resemblance of the spores shown in fig4 #dcb1 ,c1 ,d to those recently discovered by ,kidston and referred to the genus ,whittleseya 7fig4 #dbi71 and it is very probable that the striking similarity is an index of affinity4 ,ottokaria4 ,zeiller4 ,ottokaria bengalensis ,zeiller4 ,a specimen of doubtful affinity from the ,lower ,gondwana 7,karharbari beds7 of ,passerabhia1 ,india1 was originally described by ,zeiller#cif as ,feistmantelia bengalensis1 but in a postscript he substituted the name ,ottokaria on the ground that ,feistmantelia had previously been employed by ,lester ,ward4 ,fig4 #dcc is drawn from the original specimen3 it consists of a stalk attached in a slightly excentric position to an almost orbicular lamina1 #be cm4 in diameter1 with subacute marginal teeth and traversed by numerous radially disposed striations4 ,zeiller compares the fossil with ,whittleseya elegans and ,rhipidopsis ginkgoides and assigns it with some hesitation to the ,salisburieae4 ,an examination of the type-specimen led me to form the opinion that it may be a cupular organ of a ,pteridosperm that enclosed a seed4 ,the lamina is slightly concave and has the form of a shallow cup2 moreover the surface-features resemble those of a bract rather than the regularly veined lamina of a foliage-leaf4 ,the specimen bears a very close resemblance to one figured by ,bertrand#cig as the cupule of ,hexapterospermum modestae which he connects with fronds of ,neuropteris gigantea4 ,illustration3 ,fig4 #dcc4 ,ottokaria bengalensis4 7,nat4 size2 drawn from the type-specimen47 ,ottokaria occurs in association with fronds of ,glossopteris indica and with the large seeds described by ,zeiller#cih as ,cardiocarpus indicus4 ,i have lately obtained some evidence in favour of assigning ,feistmantel's seeds ,carpolithes ,milleri#cii to the genus ,glossopteris3 among several specimens from the ,lower ,gondwana rocks of ,india ,i found an example showing a seed partially covered by a scale-leaf in its natural position which appears to be identical with scale-leaves of ,glossopteris4 ,it may be that the specimen represented in fig4 #dcc belongs to ,cardiocarpus indicus1 though this is a mere guess3 my belief is that ,ottokaria is a cupular organ that enclosed the base of a seed borne on a ,pteridosperm4 ,there is little doubt that as additional data are obtained it will be found that ,pteridosperms played no inconsiderable part in the vegetation of ,gondwana ,land4 ,illustration3 ,fig4 #dcd4 ,strobilites ,milleryensis4 7,natural size2 after ,renault47 ,strobilites4 ,schimper and ,mougeot4 ,strobilites ,milleryensis 7,renault74 ,this species1 from the ,permian of ,france1 was placed by ,renault in ,cycadospadix#djj1 but having regard to the fact that it differs essentially in habit from ,mesozoic examples of that genus the provisional name ,strobilites#dja is suggested4 ,the type-specimens are long and narrow spikes or loose strobili1 #h-af cm4 long and #b-bf cm4 broad2 a stout axis bears spirally disposed bracts #h-aj mm4 long attached by a slender decurrent pedicel expanded distally into a fan-shaped laciniate lamina with a convex upper face1 and there are said to be two seeds attached to the sides of each pedicel 7fig4 #dcd74 ,the oval seeds appear to be platyspermic and resemble ,samaropsis fluitans ,daws4 ,two of the strobili figured by ,renault are attached at right angles to a second axis1 a habit suggesting comparison with that of a large compound frond4 ,renault is inclined to regard these fertile shoots as cycadean and suggests a possible connexion with the ,permian stems ,ptychoxylon or ,poroxylon1 both of which are known to have produced fairly numerous branches4 ,in habit the spikes are similar to some of the longer examples of ,cordaianthus1 but their preservation is not sufficiently good to afford accurate information as to the relation of seed to sporophyll4 ,strobilites ,milleryensis is1 perhaps1 more likely to be the fertile branch of a compound frond of a ,pteridosperm1 and it is significant that the seeds have been found in association with ,callipteris leaves4 ,,colpoxylon4 ,brongniart4 ,colpoxylon aeduense ,brongniart4 ,the genus was founded by ,brongniart#djb on a piece of stem #ae cm4 in diameter from the ,permian of the ,autun district and regarded by him as a distinct type1 with certain resemblances to recent ,cycads4 ,a thick section in the ,british ,museum1 #ac cm4 in diameter 7fig4 #dce1 ,a71 illustrates the main anatomical features described by ,renault#djc1 to whom our knowledge of the genus is chiefly due4 ,there are two large steles of irregular outline closely resembling those of ,medullosa ,leuckarti 7cf4 fig4 #daf1 ,h72 each consists of a band of secondary xylem with broad medullary rays and a narrow zone of phloem enclosing a central region composed of parenchyma1 in which strands of primary tracheids1 both reticulate and spiral1 pursue a more or less horizontal course1 associated with a few small groups of vertical xylem-strands at the inner edge of the secondary wood4 ,the manoxylic nature of the wood is clearly shown in fig4 #dcf2 the continuous ink-line marks the position of the cambium and the dots show the internal protoxylem4 ,homogeneous parenchyma surrounds the steles and beyond this is crushed tissue containing large secretory canals and nests of stereome fibres either as separate groups or in contact with the canals 7fig4 #dce1 ,c74 ,in the same peripheral tissue occur scattered collateral vascular bundles 7fig4 #dce1 ,d7 identical with those of ,myeloxylon4 ,the outer cortex of the stem is marked off from the more homogeneous inner region by a fairly distinct line where there is some indication of periderm4 ,the anatomical features are clearly shown in fig4 #dcf1 a photograph from a section in ,dr ,kidston's collection4 ,at a is an imperfectly preserved vascular bundle with a crescentic group of secondary xylem which is probably a leaf-trace that has just emerged from the secondary cylinder4 ,renault speaks of these more or less circular strands as possibly connected with reproductive shoots1 but it is more probable that they are homologous with the strands in the pericycle and inner cortex of ,medullosa and represent leaf-traces before division into smaller collateral strands4 ,renault describes the stem as possessing seven vascular cylinders in the apical region and suggests branching of the main axis as the cause of the increase in number3 there is1 however1 no evidence to support such correlation4 ,the two steles seen in fig4 #dce1 ,a1 become merged at a lower level into a single stele of sinuous form 7fig4 #dce1 ,b74 ,illustration3 ,fig4 #dce4 ,colpoxylon aeduense4 ,a4 ,diagram of a transverse section of a specimen in the ,british ,museum4 7,v4 #icic4 nat4 size47 ,b4 ,stele2 much reduced from ,renault's figure4 ,c1 ,d4 ,secretory canal with fibres and collateral vascular bundle 7,kidston ,coll41 #aidf74 ,illustration3 ,fig4 #dcf4 ,colpoxylon aeduense4 ,transverse section of half of the stem2 a1 stele of branch4 ,slightly enlarged4 7,kidston ,coll41 #aidf47 ,beyond the facts furnished by the leaf-trace bundles in the outer cortex and the occurrence of two large scars about #e cm4 in breadth on a stem figured by ,renault1 we have no positive information as to the form of the leaves or the structure of the reproductive organs4 ,there is little doubt that the fronds were large and compound like those of most species of ,medullosa4 ,there is1 however1 some slight evidence that ,alethopteris ,grandini ,brongn4 and seeds of the ,pachytesta type 7fig4 #dig7 were borne on ,colpoxylon stems2 this rests solely on the association in the ,loire coal-basin#djd of ,alethopteris fronds with stems presenting structural resemblances to ,colpoxylon aeduense4 ,the striking resemblance between ,colpoxylon and ,medullosa ,leuckarti has led certain authors#dje to propose the substitution of ,medullosa for ,colpoxylon4 ,the resemblances though close are hardly sufficient to warrant this course4 ,in ,colpoxylon the stelar system is simpler2 there is no central region with star- or plate-rings as in ,medullosa ,leuckarti but1 as in ,medullosa anglica1 the vascular tissue consists only of large steles without a medullary system4 ,colpoxylon differs from ,m4 anglica in the reduction in some parts of the stem of the vascular system to a single stele and1 moreover1 the primary portion of the steles is much more parenchymatous in structure and contains more irregularly anastomosing tracheal strands than is the case in ,m4 anglica4 ,the alteration in the pattern formed by the vascular system at different levels in some ,medullosan stems1 especially in ,colpoxylon1 may be compared with the varying disposition of the vascular strands in the thick dorsiventral rhizomes of ,polypodium heracleum ,kunz4 and ,p4 quercifolium ,l4 ,in the rhizome of ,p4 heracleum there are two vascular systems1 an outer1 cortical1 system in the form of a hollow cylinder composed of a lattice-work with polygonal meshes from which branches are given off to the roots1 and a more complex medullary system that is concerned with the emission of leaf-traces4 ,as shown by a series of drawings reproduced in an account by ,klein#djf of the anatomy of these species of ,polypodium1 the inner system of steles consists of two cylinders connected towards the upper surface of the stem by a rounded arch of vascular strands2 nearer the leaf-base the two cylinders meet and eventually a larger cylinder is produced partly from the upper halves of the two cylinders of the previous section and in part from the connecting arch3 the remains of the two smaller cylinders become connected with the outer vascular system4 ,these and other changes suggest comparison with ,colpoxylon as also with the stelar changes in the stem of ,ptychoxylon4 ,the comparison cannot be carried beyond the grosser features and is chiefly interesting as affording a further illustration of a similarity in plan between some recent ,ferns and extinct ,pteridosperms and other ,palaeozoic genera4 ,illustration3 ,fig4 #dcg4 ,rhexoxylon africanum4 ,transverse section of stem showing peripheral steles and central 7c7 stele4 7,after ,bancroft2 #b47 ,,rhexoxylon4 ,bancroft4 ,rhexoxylon africanum ,bancroft4 ,the genus ,rhexoxylon was instituted for a new type of stem represented by a single incomplete specimen from the ,karroo series of ,south ,africa3 its precise geological horizon is not known but it may be referred provisionally to the lower or ,palaeozoic portion of the series4 ,though our knowledge of the morphological features of the type-species is far from complete owing in part to the method of preservation of the specimen and in part to the destruction of the outer portion of the vascular tissue and the whole of the cortex1 ,miss ,bancroft's careful description#djg demonstrates the existence of characters which justify the employment of a new generic name4 ,rhexoxylon is more nearly related to the ,medulloseae than to any other group and is particularly interesting as the first recorded example of this group from the ,southern ,hemisphere4 ,fig4 #dcg shows a transverse section 7#g #e cm47 of the stem4 ,the ground-tissue consists of fairly large-celled parenchyma with sclerous nests and a few bands of periderm4 ,at the periphery of the stem are radially disposed groups of vascular tissue varying in size and to some extent in shape4 ,unfortunately the stem is incomplete and it is impossible to say how much vascular or other tissue originally existed beyond the present corroded edge4 ,the vascular groups1 or steles as they may legitimately be called1 follow a vertical course through the length of the block 7#fe cm47 and afford only slight evidence of branching or anastomosing4 ,a close examination of the steles shows that they consist of portions of two series1 an inner and outer set2 there is also a curved vascular band in the central ground-tissue 7fig4 #dcg1 c7 and some isolated and scattered patches of vascular elements4 ,each stele of the inner series is made up of two parts1 an outer smaller and normally orientated group of secondary xylem and a larger inversely orientated inner group of identical structure4 ,a single stele of the inner series is shown in fig4 #dch1 ,b1 ,c2 the larger inner portion consists of slightly divergent rows of tracheids and uniseriate medullary rays and is separated from the smaller portion by a narrow space1 a1 occupied by crushed tissue which may correspond to the #8partial pith' or primary xylem of a ,medullosan stele4 ,the two groups of xylem are no doubt the products of two cambium arcs1 the protoxylem of each group being situated on the flat inner face4 ,the cambium and phloem are represented only by crushed brown cells on the curved outer edge of the xylem4 ,the separate individuality of the two portions of each stele is indicated not only by the presence of the #8partial pith' but by the discontinuity of the tissue at the ends of the narrow space4 ,the tracheids seen at b1 fig4 ,c1 are in oblique longitudinal section and are probably being detached to form a leaf-trace4 ,this type of stele may be compared with the steles of ,medullosa ,solmsi 7fig4 #daf1 ,l7 but those of ,rhexoxylon differ in the lack of continuity of the secondary xylem round the narrow band of crushed primary xylem4 ,the other steles of the inner ring exhibit the same dual nature though with local modifications4 ,in the stele seen in fig4 #dch1 ,b1 there is a close approach to a continuous cylinder of secondary xylem especially on the right-hand side4 ,external to the inner series are several portions of normally orientated secondary xylem-groups 7fig4 #dcg73 these probably represent a second series of steles separated from the inner series by a narrow crushed arc of tissue on which the protoxylem strands of the outer groups abut4 ,the xylem of the outer steles agrees in its normal orientation with the outer and smaller part of the inner steles and1 as there is no accompanying group of inversely orientated xylem corresponding to the larger mass of secondary xylem of the inner series1 the outer strands are designated partial steles4 ,the central stele consists of two curved irregular bands composed of vertically and obliquely running tracheids3 the central part of this stele consists of crushed tissue that probably represents primary xylem like that between the two parts of each of the peripheral steles4 ,illustration3 ,fig4 #dch4 ,rhexoxylon africanum4 ,a1 radial wall of tracheid2 ,b1 ,c1 peripheral steles2 a1 primary portion of stele2 b1 lateral strand4 7,after ,bancroft47 ,rhexoxylon differs from the usual ,medullosan type in the structure of the secondary xylem which is composed of tracheids with an ,araucarian form of pitting3 there are usually two alternate rows of contiguous pits 7fig4 #dch1 ,a7 and occasionally one or three rows4 ,the medullary rays are uniseriate and #c to #ae cells in depth1 a feature characteristic of coniferous wood and not of the wood of the ,medulloseae4 ,in the absence of more complete information as to the anatomical structure of this stem and of all information as to the leaves or reproductive organs it is impossible to fix with precision the systematic position of the genus4 ,it is1 however1 clear that ,rhexoxylon is closely connected with ,medullosa in certain features though in the structure of the wood it exhibits important peculiarities4 ,the imperfectly known stem ,cladoxylon ,kidstoni#djh shows a fairly close agreement with the ,african plant in the form of the steles 7fig4 #dfj7 but the pitting is scalariform4 ,,sutcliffia4 ,scott4 ,sutcliffia insignis ,scott4 ,the generic name ,sutcliffia was given by ,dr ,scott#dji to a peculiar type of stem from the ,lower ,coal ,measures of ,shore1 ,lancashire1 in recognition of the valuable services rendered to ,palaeobotany by the late ,mr ,w4 ,h4 ,sutcliffe1 the owner of the colliery from which several new types of plants have been obtained4 ,two stems are recorded1 the type-specimen and a more recently discovered stem1 also from ,shore1 described by ,miss de ,fraine#daj1 which differs in several particulars from ,dr ,scott's species4 ,in view of the well-marked peculiarities of the second stem it is convenient to speak of it as forma instead of including it without a distinctive epithet in ,sutcliffia insignis4 ,we know nothing of the reproductive organs of the genus4 #a4 ,sutcliffia insignis1 forma 4 ,this consists of a piece of stem approximately #ab #g cm4 in diameter characterised by a broad cortex of parenchyma with secretory sacs and ducts and strands of mechanical tissue 7fig4 #dci1 ,a74 ,decurrent and massive leaf-bases form a prominent feature as in the stem of ,medullosa anglica4 ,the stele1 though compressed before petrifaction1 was probably not quite cylindrical but more or less polygonal or broadly triangular in section2 it consists of groups of large primary tracheids 7#cej in diameter7 with numerous bordered pits 7fig4 #dci1 ,b1 and fig4 #ddj7 embedded in an anastomosing system of parenchyma containing scattered secretory sacs1 a type of protostele like that of ,heterangium and ,medullosa anglica except in the possession of exarch protoxylem strands4 ,the metaxylem tracheids contiguous to the external protoxylem elements have a dense spiral or scalariform type of pitting4 ,in the lower part of the stem the primary xylem is enclosed by a cambium which has added a few secondary tracheids 7#abj in diameter71 but in the upper part of the specimen the cambium is only partially developed and the addition of secondary xylem has hardly begun 7fig4 #ddj74 ,a narrow band of secondary phloem was recognised in places consisting of small-celled parenchyma with some sieve-tubes and medullary rays continuous internally with the parenchyma of the primary stele4 ,in close association and occasionally in organic connexion with the surface of the stele are several tangentially elongated and large groups of vascular tissue associated with smaller oval strands varying considerably in size4 ,these groups1 designated meristeles 7,fig4 #dci1 ,a71 are identical in structure with the main stele and are occasionally invested by a feebly developed zone of secondary xylem and phloem4 ,the meristeles are detached at intervals from the parent stele around which they form by anastomoses an irregular network3 the larger meristeles give off smaller strands and from these the actual leaf-traces are produced by subdivision4 ,it appears1 however1 that in this type the meristeles are not completely used up in the production of the leaf-traces1 portions of them behaving as cauline vascular strands4 ,a protoxylem of a meristele still attached to the central protostele occupies an internal position1 and at a higher level1 as separation of the meristele is effected1 the spiral tracheids occur on the inner face4 ,new meristeles are given off at intervals from the main stele #8to compensate for those parts of the reticulum which were used up in the formation of leaf-trace strands#daa4' ,the meristeles form the starting-point for the leaf-traces1 an intermediate system between the main stele and the actual leaf-traces2 they differ1 therefore1 from the parent leaf-traces of ,medullosa anglica1 which are completely used up by repeated subdivision4 ,moreover in ,sutcliffia the leaf-bundles are concentric and not collateral4 ,illustration3 ,fig4 #dci4 ,sutcliffia insignia ,scott4 ,a1 ,b1 ,e1 forma 4 7,after ,scott47 ,c1 ,d1 forma 4 7,after de ,fraine47 ,a4 ,transverse section of stem2 a1 b1 double rows of leaf-trace bundles4 ,the larger black masses are the meristeles2 the smaller patches represent bundles derived from the meristeles4 ,b4 ,longitudinal section of a radially symmetrical bundle from a leaf-base4 ,c4 ,the junction between the primary and secondary xylem4 ,d4 ,vascular system in transverse section3 m1 m1 meristeles2 s1 main stele2 e1 extrafascicular strands2 lt1 leaf-traces2 c1 secondary cortex4 ,e4 ,vascular bundle from petiole showing a ring of large sieve-tubes surrounding the xylem1 and portions of stereome strands4 ,illustration3 ,fig4 #ddj4 ,sutcliffia insignis4 ,part of the primary xylem showing on the upper edge the beginning of secondary growth4 7,cambridge ,botany ,school1 #efj47 ,a conspicuous feature of the stem of forma is the occurrence of two double rows of vascular strands stretching across the cortex 7fig4 #dci1 ,a1 a1 b74 ,these are interpreted by ,scott as downward continuations in the stem of the inner surface of leaf-bases4 ,the outer cortex of the stem and leaf-bases has hypodermal strands of stereome which remain separate or rarely anastomose1 and form a superficial zone exactly like that of some species of ,medullosa4 ,the leaf-trace bundles may be radially symmetrical or unilateral in the arrangement of the xylem which is in all cases completely surrounded by phloem4 ,fig4 #dci1 ,b1 shows part of a longitudinal section of a large leaf-trace bundle3 spiral protoxylem elements 7px7 abut on the phloem 7ph7 and are succeeded to the left by narrow scalariform and large reticulately pitted tracheids4 ,in the larger and radially constructed traces there are several protoxylem-strands distributed over the surface of the xylem1 while in the smaller unilateral traces there may be one or two protoxylem strands4 ,a characteristic feature of the xylem of the leaf-traces is the admixture of parenchyma with the tracheids 7fig4 #dci1 ,b1 ,e7 and another noteworthy character is the occurrence of large thin-walled tubes in the phloem described by ,scott as sieve-tubes and compared with the large sieve-tubes in ,marattiaceous leaf-bundles4 ,immediately internal to the hypoderm is a row of leaf-bundles 7fig4 #dci1 ,a7 each of which is accompanied by stereome strands4 ,the petioles1 which reach a diameter of #ab cm41 contain numerous1 occasionally anastomosing1 concentric bundles4 ,nothing is known of the fronds as a whole beyond the fact that they are spirally disposed and had decurrent bases of large dimensions in proportion to the stem4 ,sutcliffia insignis1 forma 4 ,this form1 described by ,miss de ,fraine as ,sutcliffia insignis#dab1 is represented by a stem rather smaller than the type-specimen described by ,scott1 though it is probably an older example of the same species4 ,it is distinguished by a greater development of secondary xylem and phloem both on the main stele and the meristeles2 it differs also in the absence of the greater part of the cortex and leaf-bases which have been cut off as the result of the formation of a deep-seated periderm 7fig4 #dci1 ,d1 ,c74 ,the meristeles are smaller and fewer than in the larger form and are distinguished by some other peculiarities4 ,at m in fig4 #dci1 ,d1 a meristele is seen attached to the main stele4 ,in ,sutcliffia insignis forma the main stele is enclosed by an irregular network of subsidiary steles or meristeles and these form the points of departure of the leaf-traces1 but the meristeles are not completely used up in the process of conversion into leaf-traces4 ,in ,sutcliffia insignis forma the meristeles agree in structure with the main stele except in the smaller amount of secondary tissue3 they do not1 however1 form a network as in forma but occur as strands parallel to the central stele1 #8giving off leaf-traces and ultimately dividing up into smaller strands1 often unequal in size1 the primary wood of the meristeles being entirely used up in the production of radially symmetrical or unilateral bundles4' ,in this respect1 as ,miss de ,fraine points out1 forma agrees more closely than forma with ,medullosa anglica and supports ,scott's view that ,sutcliffia is a primitive type of ,medullosan stem4 ,the leaves were given off at fairly long intervals as in some species of ,medullosa3 the leaf-traces are exarch and similar to those of the type-species4 ,the most striking feature of the new stem is the presence of a vascular network 7fig4 #dci1 ,d1 e7 which encloses both the main steles and the meristeles2 it consists of extrafascicular strands composed of normally orientated bands of secondary xylem and phloem often assuming a fan-like arrangement and occasionally almost concentric or inversely orientated4 ,these strands are always accompanied by short1 usually reticulate1 tracheids on the inner margin of the xylem3 similar isodiametric tracheids also occur in the pericyclic region4 ,the extrafascicular strands are believed to be secondary structures phylogenetically independent of the meristeles and main stele1 comparable with the successive cylinders or arcs of secondary xylem and phloem in some recent ,cycads and in some species of ,medullosa#dac4 ,the stele is exarch and roughly triangular2 except in the broader zone of secondary tissue it agrees with the protostele of forma 4 ,the secondary xylem 7fig4 #dci1 ,c7 possesses numerous medullary rays #c-d cells broad and of considerable depth3 the secondary phloem is characterised by the presence of thick-walled elements1 presumably sieve-tubes1 like those of ,medullosa ,leuckarti and ,m4 anglica4 ,the ground-tissue is rich in secretory tissue and the stem-surface1 from which the leaf-bases have been detached1 is limited by a wide zone of secondary tissue produced by a phellogen4 ,sutcliffia ,williamsoni 7,seward74 #ahgf4 ,myelopteris 7pars7 ,williamson1 ,phil4 ,trans4 ,r4 ,soc4 ,vol4 #aff1 ,pl4 ii4 figs4 #g1 #h2 ,pl4 iv4 fig4 #ag4 #ahic4 ,rachiopteris ,williamsoni ,seward1 ,ann4 ,bot4 ,vol4 vii4 p4 #a4 #ahid4 ,rachiopteris ,williamsoni ,seward1 ibid4 ,vol4 viii4 p4 #bjg1 ,pl4 xiii4 #aijf4 ,sutcliffia ,williamsoni ,scott1 ,trans4 ,linn4 ,soc4 ,vol4 vii4 pt iv4 p4 #fb4 ,in an account of ,myelopteris 7 ,myeloxylon7 published in #ahgf ,williamson included some sections of petioles from the ,lower ,coal ,measures which ,i afterwards with his concurrence transferred to the genus ,rachiopteris as ,r4 ,williamsoni4 ,in ,rachiopteris ,williamsoni the vascular bundles are concentric and not collateral1 and are further distinguished from those of ,myeloxylon by the association of parenchyma with the tracheids4 ,in the arrangement of the bundles and in the structure of the ground-tissue the petioles of ,rachiopteris ,williamsoni agree with those of ,myeloxylon4 ,an outstanding feature of the vascular strands of the former is the occurrence at fairly regular intervals in the peripheral part of the phloem of comparatively large tubes described by me as secretory canals on the ground that evidence was furnished of their development by the schizogenous separation of cells to form a central canal4 ,the canals were compared with the large sieve-tubes of the ,marattiaceae1 but with the qualification that #8their mature form and their manner of development are strongly suggestive of small secretory canals4' ,nothing was known as to the stem which bore these petioles until ,scott's discovery of ,sutcliffia with vascular bundles in the cortex and leaf-bases of the same type as those of ,rachiopteris ,williamsoni4 ,as ,scott says1 there are a few distinguishing features which suggest that ,r4 ,williamsoni is not specifically identical with the petioles of ,sutcliffia insignis1 though the agreement is such as to justify the substitution of ,sutcliffia for ,rachiopteris4 ,the tubular elements in the phloem which ,i considered to be secretory canals are regarded by ,scott and ,miss de ,fraine as sieve-tubes4 ,miss de ,fraine gives an excellent summary of our knowledge of the genus and discusses1 in the light of the additional facts furnished by the second stem1 the position of ,sutcliffia in a phylogenetic series4 ,the new form strengthens the comparison instituted by ,scott between ,sutcliffia and ,medullosa and gives support to a close connexion between the ,medulloseae and the ,cycadaceae4 ,scott lays stress on the fact that the ,medulloseae1 except ,sutcliffia1 are polystelic1 while the ,cycads1 at least the adult stems1 are monostelic4 ,the views of ,worsdell and other botanists who believe that the ,medulloseae and the ,cycads are intimately related are discussed on another page3 in reference to these views ,miss de ,fraine adds a caveat as to the danger of attaching excessive importance to evidence based on seedling anatomy when we are concerned with broad phylogenetic questions4 ,the stele of a cycadean stem may be derived from a protostelic type such as that of ,sutcliffia by the gradual disappearance of the internal tracheids3 in ,sutcliffia1 as in some ,cycads and species of ,medullosa1 extrafascicular strands and cylinders are a characteristic feature and these may well have arisen independently of the central stele in response to physiological requirements4 ,from such a type as ,sutcliffia evolution may have proceeded along two lines2 in one direction new types were produced in which increasing complexity1 as represented by a multiplication of steles1 was an outstanding feature4 ,these forms1 illustrated by ,medullosa anglica and other more elaborate species1 proved inefficient and were unproductive4 ,along another line the protostelic condition was maintained though in some cases extrafascicular strands or cylinders and cortical steles were superadded3 it was this line that led to the recent ,cycads4 ,general considerations suggested by the anatomical features of ,medullosa4 ,a comparison of the stems described under the generic name ,medullosa reveals a considerable range in the grosser anatomical features superadded to certain fundamental characters denoting a common origin#dad4 ,if additional data were available giving us a fuller knowledge of individual plants differences between species would be more clearly defined and would provide adequate grounds for the institution of new genera for some of the types now included in the comprehensive genus ,medullosa4 ,a proposal by ,dr ,lotsy#dae to adopt the names ,pecopteromedullosa and ,neuropteromedullosa rests primarily on the relatively unimportant difference between the fronds associated with certain ,medullosan stems and1 as ,scott#daf points out1 this two-fold division if applied to such a species as ,medullosa ,leuckarti would result in its separation from species which anatomically are clearly of the same generic type4 ,in ,medullosa anglica1 one of the oldest and simplest types1 there are three steles of equal importance1 and each of them is practically identical with the single stele of ,heterangium4 ,each stele--as indeed all ,medullosan steles--consists of a strand of primary xylem enclosed by secondary xylem and phloem1 and it is obvious that the development of a constantly increasing cylinder of secondary conducting tissue about three centres would lead to serious mechanical difficulty3 a stem constructed on the plan of ,medullosa anglica or the smaller ,m4 pusilla could not increase the thickness of its secondary vascular tissue beyond a certain point without detriment to its efficiency4 ,in some types this difficulty is partially overcome by the production of complete concentric cylinders of centrifugally developed conducting tissue external to an inner system of concentric steles agreeing individually with those of ,heterangium 7fig4 #dae1 ,b74 ,medullosa anglica1 regarded from the point of view of the architectural efficiency of its vascular system1 affords a much less promising point d'appui for further evolution than some of the forms described under ,medullosa stellata in which the mechanical impasse is avoided by the adoption of the cycadean plan as represented by such genera as ,cycas and ,macrozamia4 ,the ,english species ,medullosa centrofilis 7fig4 #dag7 affords the first example of a characteristic ,medullosan feature1 namely the presence of a small concentric stele in the central region of the stem3 this so-called star-ring differs not only in its smaller dimensions but in its more cylindrical form from the larger peripheral steles4 ,in the later ,permian species1 e4g4 ,medullosa porosa and ,m4 ,solmsi1 the single star-ring of the older ,m4 centrofilis is replaced by a large number of precisely similar conducting strands4 ,these star-rings are structurally comparable with the cortical steles of ,cycas and1 in position1 with the medullary system of bundles in a ,macrozamia2 they are essentially cauline and take no part in the emission of leaf-traces4 ,medullosa ,leuckarti 7fig4 #daf1 ,h7 resembles in its vascular plan ,m4 centrofilis1 but in this larger stem there are several star-rings and the enlarged peripheral steles are more or less sinuous4 ,in ,medullosa ,solmsi 7fig4 #daf1 ,e7 the star-rings are still more numerous and the main vascular system consists of a double series of concentric steles1 each agreeing with the larger peripheral steles of ,m4 ,leuckarti4 ,some of the forms included in ,medullosa stellata appear to be very different from ,m4 anglica and ,m4 ,leuckarti 7cf4 fig4 #daf1 ,f1 ,a1 ,h71 but their similarity is apparent if we imagine ,medullosa anglica with only one main stele 7with the addition of star-rings7 which is stretched tangentially until it becomes a long and narrow plate-ring and is then rolled into a hollow cylinder like that in fig4 #daf1 ,d4 ,a modification of the tubular type of stele is seen in ,medullosa stellata var4 corticata 7fig4 #daf1 ,g7 in which the vascular cylinder is broken up into two or more curved plate-rings1 a change superficially similar to that by which a dictyostele is produced from a solenostele1 but in ,medullosa it is not the overlapping of leaf-gaps that is the cause of the change4 ,a striking feature in the stem of ,medullosa stellata represented in fig4 #daf1 ,d and ,f 7especially ,f71 is the inequality in breadth of the centrifugal and centripetal xylem3 this inequality is an expression of the difficulty caused by the presence of an internal as well as an external addition of secondary conducting tissue4 ,a limit is set to the production of secondary centripetal xylem by the space available for extension1 whereas there is unlimited room for increase in the case of the centrifugal tissue4 ,this tendency to a greater development of xylem and phloem on the outer side of the primary portion of the steles is illustrated also in ,m4 ,solmsi var4 lignosa 7fig4 #daf1 ,l7 where the outer of the two series of peripheral steles has a much larger proportion of centrifugal xylem4 ,in ,m4 anglica the secondary xylem on the inner side of the steles is not infrequently broader than the corresponding tissue on the abaxial side#dag2 but this is exceptional in the genus4 ,a further development of centrifugal conducting tissue without any corresponding development of centripetal tissue is effected in certain cases 7fig4 #daf1 ,k1 ,l7 by the addition of concentric cylinders of centrifugal xylem and phloem beyond the original concentric steles4 ,the type illustrated by ,medullosa ,solmsi var4 lignosa and ,m4 stellata var4 gigantea 7fig4 #daf1 ,l1 ,k7 at once suggests comparison with stems of ,cycas1 ,macrozamia1 and ,encephalartos1 the chief difference being the presence in ,medullosa of an inner series of concentric steles and a central ground-tissue containing star-rings1 though the latter may be regarded as corresponding to the medullary system of bundles in ,macrozamia4 ,in ,macrozamia the central region of the stem is considered to be the pith of a monostelic stem1 whereas in ,medullosa the stem is polystelic4 ,in recent cycadean stems it is not uncommon to find patches of inversely orientated xylem and phloem internal to one or more of the cylinders of centrifugal vascular tissue4 ,these abnormal developments are considered by ,worsdell#dah to be relics of the inner portions of concentric steles possessed by the ,medullosan ancestors of recent ,cycads4 ,this interpretation affords a means of bringing into closer relationship the polystelic ,medulloseae and the monostelic ,cycadaceae1 the apparent simplicity of the latter being the result of the progressive loss of centripetal xylem and phloem1 the normal cycadean cylinder being therefore regarded as a one-sided remnant of a concentric ,medullosan stele4 ,in other words1 the ,cycads are descended from polystelic ancestors4 ,as further evidence in support of this view ,worsdell points to the occurrence of concentric steles in the cortex of ,cycas and their occasional presence in the pith of other genera4 ,matte#dai has shown that in the seedling stem of ,encephalartos ,barteri 7fig4 #cif1 ,k7 there are three concentric steles each similar to a normal ,medullosan stele3 at a higher level in the axis the steles become #8unrolled' and assume the form of one-sided cylinders of centrifugal xylem and phloem4 ,in the peduncles of some recent ,cycads1 e4g4 ,stangeria1 there is a tendency towards a somewhat irregular orientation of the collateral bundles that constitute the vascular cylinder1 and tracheids occasionally occur internal to the protoxylem of the individual bundles#dbj4 ,worsdell regards these features as evidence of a ,medullosan ancestry4 ,if the sinuous plate-rings of a stem of ,medullosa ,leuckarti 7fig4 #daf1 ,h7 were broken up into separate portions and wholly or in part deprived of the centripetal xylem1 the result would be an arrangement of bundles comparable with that in a ,stangeria peduncle#dba4 ,the scattered centripetal tracheids discovered by ,scott in ,stangeria and other cycadean peduncles are interpreted by ,scott and by ,worsdell as relics of some ancestral centripetal xylem1 but with this important difference in the point of view2 ,scott believes that they represent the almost completely aborted centripetal xylem of a single stele like that of ,lyginopteris1 while ,worsdell sees in them fragmentary vestiges of the central primary xylem of two or more ,medullosan steles4 ,an abnormal seedling of ,araucaria ,bidwillii described by ,shaw#dbb exhibits features analogous to those in some cycadean seedlings3 within the normal stele a cambium forms an inversely orientated vascular cylinder which at a lower level becomes continuous with the outer centrifugal tissue1 the whole vascular system being eventually represented by two concentric steles4 ,the polystelic stage is a development of a monostelic condition1 and the inner or inverted portion of each of the two concentric steles is derived from an inversely orientated cylinder in the central region of the root4 ,this abnormal root does not1 however1 supply an argument in favour of the derivation of a monostelic type of stem from one that was polystelic1 but it shows a close relation between the two plans in one organ4 ,the seedling is not altogether normal in form apart from structure and it is not improbable that the anatomical abnormality is connected with some pathological cause4 ,it has been suggested#dbc that ,worsdell attaches too much phylogenetic significance to the irregularities in the disposition and form of the vascular bundles in the peduncle of ,stangeria1 and the criticism that insufficient allowance is made for the possible reaction on structure of the special physiological requirements of reproductive shoots is well founded4 ,granting an overestimate of the arguments drawn from the occasional occurrence of concentric vascular strands1 a considerable body of evidence remains in favour of ,worsdell's main contention4 ,mrs ,thoday#dbd has drawn attention to certain features exhibited by the inflorescence-axes of ,welwitschia1 particularly the occurrence of concentric and inversely orientated bundles1 similar to those characteristic of the seedling of ,cycas siamensis#dbe described by ,matte1 and to anatomical characters occasionally present in adult cycadean stems and normally represented in ,medullosa4 ,she is of opinion that the occurrence in ,welwitschia of certain ,medullosan features has a phylogenetic significance4 ,the differences between the ,gnetales1 ,medulloseae1 and ,cycadales are considerable1 and it would seem unlikely that the anatomical resemblances described by ,mrs ,thoday are of great value as criteria of close relationship4 ,the comparison of ,lagenostoma with gnetalean seeds is alluded to elsewhere4 ,to the statement that the presence of concentric and inversely orientated steles in ,welwitschia are reminiscent of the polystelic ,medulloseae1 ,mrs ,thoday adds the qualifying remark that the occurrence of four concentric groups of vascular tissue in the hypocotyl of ,welwitschia is not sufficient to justify the conclusion that the ancestral type was polystelic4 ,this reservation accords with the contention of ,scott and other botanists1 that the occasional occurrence in cycadean seedlings and adult stems of anatomical features suggestive of polystely does not in itself furnish an adequate reason for doubting that the apparent monostely of ,cycads is phylogenetically what it seems to be1 namely1 an indication of monostelic ancestry4 ,this brings us to the question of a possible monostelic ancestor4 ,it may be that the ,upper ,carboniferous genus ,sutcliffia affords a clue to the problem of the origin of the polystelic type illustrated in various forms by ,medullosa4 ,the protostele of ,sutcliffia bears a close resemblance to each of the three steles of ,medullosa anglica2 the fact that ,sutcliffia is exarch and that ,medullosa anglica has mesarch xylem is of secondary importance1 particularly as exarchy is represented within the genus ,medullosa4 ,the extrafascicular strands of xylem and phloem and the accessory strands are points in which ,sutcliffia and ,medullosa anglica agree and1 as ,miss de ,fraine#dbf adds1 the meristeles of ,sutcliffia may be homologous with the leaf-trace strands of ,medullosa4 ,scott#dbg gave expression to the characters shared by these two types by describing ,sutcliffia as the most primitive of the ,medulloseae4 ,it is suggested that the protostelic axis of ,sutcliffia may be regarded as the starting-point of the monostelic ,cycads1 the central mass of tracheal tissue being replaced by a parenchymatous pith1 while the extrafascicular and accessory strands arose independently of the central stele in response to increased physiological demands consequent on the increase in size of the stem4 ,from the same starting-point evolution may have progressed along another line through such a type as ,medullosa anglica leading to the more complex ,permian species of ,medullosa4 ,chodat's view#dbh that the ,medulloseae are ,protocycadaceae1 if we include ,sutcliffia as well as ,medullosa in the ,medulloseae1 is probably correct4 ,there is clear evidence of a close bond of union between recent ,cycads and the ,medulloseae1 and ,sutcliffia offers a possible means of deriving complex polystelic types from a monostelic ancestor4 ,worsdell's opinion#dbi that the stele of ,lyginopteris affords evidence of derivation from a polystelic ancestor and is not homologous with the true monostele of ,heterangium is opposed to the undoubted signs of intimate connexion exhibited by these genera4 ,the ,lyginopterideae are1 as ,scott#dcj says1 a less advanced group than the ,medulloseae and1 it may be added1 they are more remote from the modern representatives of the ,cycadales4 ,the ,lyginopterideae and the ,medulloseae are probably offshoots of a common stock1 but the ,medulloseae occupy a position farther removed from the filicinean ancestry than ,heterangium and ,lyginopteris#dca4 ,the relative meagreness of our knowledge of the reproductive organs of the ,medulloseae gives precedence to anatomical data in phylogenetic considerations1 but the evidence furnished by ,trigonocarpus and other seeds that may fairly be assigned to ,medullosan plants is in harmony with the conclusions based on vegetative characters with regard to a close affinity between the ,medulloseae and ,cycads4 ,the comparative examination of recent ,cycads naturally suggested by any attempt to compare the group as a whole with ,palaeozoic types leads to some apparently contradictory results4 ,the habit of the megasporophyll of ,cycas is usually quoted as a primitive attribute3 the close resemblance in plan and in manner of occurrence on the stem between megasporophylls and foliage leaves recalls both ,ferns and ,medullosan fronds4 ,on the other hand the production of eight body-cells in the pollen-tube of ,microcycas#dcb in place of the usual single cell may also be regarded as a primitive character4 ,it is perhaps possible1 as ,miss ,dorety#dcc says1 that the polyspermy may be a case of recurrence and not a direct inheritance4 ,microcycas differs from ,cycas in having only one vascular cylinder1 and if the presence of several concentric cylinders in ,cycas be interpreted as an indication of a closer connexion with a ,medullosan ancestry1 the ,microcycas type would represent a more advanced stage in evolution4 ,attempts to arrange plants according to a natural sequence are frequently frustrated by instances of unequal progress in the development of vegetative and reproductive organs2 one or other set of members lags behind2 some characters point to the retention of primitive traits while others indicate a marked progressive tendency4 ,it is noteworthy that the ,mesozoic ,bennettitales are characterised by a greater simplicity of stem-structure than is the rule in recent ,cycads1 and both in their vegetative features and in the structure of the seeds they are further removed from the ,medullosan type4 ,illustration3 ,fig4 #dda4 ,steloxylon ,ludwigii4 ,a1 surface-view 7longitudinal7 of stem showing leaf-bases4 7,after ,solms-,laubach47 ,b1 longitudinal section showing anastomosing vascular strands4 ,c1 steles1 the lower one showing the emission of a leaf-trace4 7,b1 ,c1 after ,schenk47 ,,ii4 ,a4 ,,steloxyleae4 ,steloxylon4 ,solms-,laubach4 ,steloxylon ,ludwigii 7,goeppert and ,stenzel74 ,the genus is founded on a piece of stem from ,siberia1 possibly of ,permian age though not improbably older1 which was originally described as ,medullosa ,ludwigii#dcd4 ,it is characterised by numerous cylindrical and band-like vascular strands forming an irregular anastomosing system 7fig4 #dda1 ,b7 and by crowded spiral leaf-scars on the exposed face4 ,the appearance presented by the transverse section figured by these authors1 while suggesting comparison with ,medullosa1 reveals a distinctive character1 namely the absence of a definite peripheral system of vascular rings such as forms a striking feature of the continental ,medulloseae4 ,a more complete description was afterwards published by ,schenk#dce who recognised more fully the peculiar features and hinted at the possibility that the species might more appropriately be regarded as a member of a distinct group4 ,solms-,laubach#dcf went a step further and instituted the generic name ,steloxylon1 and in a later publication gave a fuller account of the anatomical characters4 ,the complete stem must have reached a diameter of approximately #ac cm4 ,the homogeneous ground-tissue forms a matrix enclosing an anastomosing vascular system of cylindrical or oval steles 7fig4 #dda1 ,c74 ,each strand consists of a band of secondary xylem tracheids with one or several rows of circular or oval bordered pits on the radial walls and narrow medullary rays usually #a-b cells broad and #a-d cells deep1 though occasionally deeper4 ,no phloem is preserved4 ,the tissue in the centre of each stele is very imperfectly preserved1 but it is clear that the secondary xylem enclosed a central region 7#8partial pith'7 like that in the steles of a ,medullosa1 doubtless consisting of primary xylem and conjunctive parenchyma4 ,the stem is covered with leaf-bases of oval or circular section and between them are small organs1 probably multicellular hairs 7fig4 #dda1 ,a74 ,a leaf-base consists of an outer zone of strengthening tissue and a parenchymatous ground-tissue traversed by two or more small vascular strands which assume various forms4 ,these petiolar strands are simply portions of the main vascular system which bend outwards at the periphery of the anastomosing network4 ,the more noteworthy features in which ,steloxylon differs from ,medullosa1 particularly such species as ,m4 stellata and ,m4 ,leuckarti1 are 7i7 the crowded and comparatively small leaf-bases in place of the massive decurrent petioles of ,medullosa2 7ii7 the supply of the leaves by compact branches of the stelar network instead of the bundles detached as leaf-traces from a stem-stele of ,medullosa 7the origin of a leaf-trace in ,steloxylon is shown in fig4 #dda1 ,c72 7iii7 the absence of a peripheral system of vascular plate-rings and the irregular distribution of cylindrical and plate-steles in the ground-tissue4 ,nothing is known of the reproductive organs or leaves beyond the structure of the attached leaf-bases4 ,the opinion expressed by ,p4 ,bertrand#dcg that the fossil described by ,stenzel as ,asterochlaena 7,clepsydropsis7 kirgisica is the petiole of ,steloxylon was abandoned after the additional facts published by ,solms-,laubach4 ,as regards the affinities of ,steloxylon3 the structure of the steles agrees closely with that of the star- and plate-rings of a ,medullosa1 while the pitting of the tracheids is more like that in ,medullosa than ,cladoxylon4 ,in the tendency to a more radial than tangential disposition of the band-like steles ,steloxylon recalls ,cladoxylon rather than ,medullosa1 but in ,cladoxylon the vascular system does not form an irregular network as in ,steloxylon4 ,the information as to the structure of the primary xylem is very meagre1 but it points to a closer connexion with ,medullosa than with ,cladoxylon4 ,on the whole ,steloxylon may perhaps be defined as a genus allied to the ,medulloseae in the anatomical features of the stem more closely than to other genera1 but sufficiently distinct to be excluded from the ,medulloseae as at present understood#dch4 ,,chapter ,,xxxi4 ,,pteridosperms ,,represented ,,by ,,seed-,,bearing ,,leaves ,,only ,,or ,,leaves ,,in ,,constant ,,association ,,with ,,seeds4 ,before describing other genera represented by petrified vegetative organs exhibiting in their anatomical features points of contact with the ,medulloseae1 a short account is intercalated of some imperfectly known seed-bearing fronds and seeds belonging to the ,pteridosperms but which do not afford sufficient data to admit of their reference to a more precise position in a natural classification4 ,pecopteris ,pluckeneti 7,schlotheim74 ,in the section in ,volume ii4 devoted to the genus ,pecopteris reference was made to the species ,p4 ,pluckeneti#dci1 further treatment being deferred until other ,pteridosperms had been described4 ,the fern-like fronds originally described by ,schlotheim as ,filicites ,pluckeneti#ddj and afterwards transferred by ,brongniart and other authors to ,pecopteris#dda are now recognised as the leaves of a ,pteridosperm4 ,some doubt has been expressed as to the specific identity of the specimens figured by ,schlotheim and ,brongniart respectively1 but ,potoni's examination of the type-specimen of the earlier author convinced him that ,brongniart's leaves were correctly named4 ,the large fronds of ,pecopteris ,pluckeneti are characterised by the bifurcation of the principal axis which bears opposite pairs of bi- or tri-pinnate branches and in the angles of the bifurcations of the rachis undeveloped buds occur on prolongations of the axis1 a habit recalling recent species of ,gleichenia#ddb 7figs4 #bbe and #bbf1 vol4 ii474 ,the variation in the form of the pinnules is shown in fig4 #ddb1 ,a1 which represents both the apical portion and parts of pinnae #aj cm4 lower on the rachis of a large leaf from the ,coal ,measures of ,radstock4 ,the species is characteristic of the ,upper ,coal ,measures and is recorded also from ,permian strata4 ,in #ahhc ,sterzel adopted for this species the generic name ,dicksonites because of the occurrence of shallow circular cups at the end of the lowest lateral vein on some of the pinnules which he believed to be sori of the ,cyatheaceous type4 ,the cups have an involute margin and occasionally a small scar in the centre 7fig4 #ddb1 ,b74 ,stur#ddc declined to accept ,sterzel's evidence as satisfactory and suggested a fungal origin for the sorus-like impressions1 a view1 as ,sterzel objected1 that is rendered improbable by the constant position of the single cups on several pinnules4 ,the nature of ,sterzel's #8sori' has not been demonstrated3 it is suggested by ,grand',eury#ddd that they mark the position of microsporangia4 ,some seed-bearing specimens in ,dr ,kidston's collection show cups1 like those figured by ,sterzel1 on pinnules from which the seeds have fallen1 and it is not improbable that they are the scars of seeds4 ,in #aije ,grand',eury published a description and photographs of specimens of ,p4 ,pluckeneti from the ,st tienne coal-field showing hundreds of well-preserved seeds1 many of them attached to pinnules characterised by a very slightly reduced lamina4 ,some fronds were found to be entirely fertile1 while others bore both sterile and fertile pinnae4 ,the smallest seeds1 #e mm4 long and #c mm4 broad1 were found at the tips of unexpanded leaves3 the mature seeds1 only slightly larger1 agree in their broadly oval form and narrow marginal #8wing' with small examples of ,samaropsis#dde4 ,the seeds were figured by ,grand',eury#ddf in an earlier work as ,carpolithes granulatus4 ,they are believed to have hung free from the lamina1 a conclusion based on the position of the seeds relative to the plane of the pinnule in well-preserved examples4 ,prof4 ,zeiller informs me that he is by no means certain that ,grand',eury's seed-bearing fronds should not be referred to ,pecopteris ,sterzeli2 but as that species and ,p4 ,pluckeneti are very closely allied forms and may well have borne the same general type of fructification1 the question of specific difference does not affect the significance of ,grand',eury's discovery4 ,a statement was made in vol4 ii4#ddg1 quoted from ,grand',eury1 that the fronds of ,p4 ,sterzeli were borne on a ,psaronius stem1 but ,prof4 ,zeiller told me that in his opinion the fronds and stem are merely in association and not in organic contact4 ,it is probable that the ,psaronius stem bore fronds of some species of ,pecopteris with sori of the ,asterotheca or ,scolecopteris type and not seeds4 ,pecopteris ,pluckeneti and ,p4 ,sterzeli are no doubt the fronds of a ,pteridosperm#ddh1 but apart from the seed-impressions there is no evidence as to the nature of the reproductive organs or stem4 ,the form of the seeds with a fairly thick sarcotesta1 which gives them a winged appearance1 suggests a member of the ,medulloseae rather than a plant with seeds like those of ,lyginopteris and ,heterangium4 ,illustration3 ,fig4 #ddb4 ,pecopteris ,pluckeneti4 ,a1 apex and lower pinnae 7,kidston ,coll41 #bcd72 ,b1 pinnule with supposed sorus 7after ,sterzel72 ,c1 pinnule with seeds 7after ,zeiller74 ,eremopteris artemisaefolia ,steinberg with ,samaropsis acuta ,lindley and ,hutton4 ,the generic name ,eremopteris was instituted by ,schimper for a type of frond from the ,coal ,measures of ,newcastle described by ,sternberg as ,sphenopteris artemisaefolia4 ,he included also a second species1 ,e4 ,neesii1 from the ,permian of ,bohemia3 this was removed by ,zeiller to ,callipteris4 ,the type-species of ,eremopteris is included in this chapter on the ground that the almost constant association with the fronds of seeds comparable with those described by ,white as ,aneimites 7,wardia7 fertilis affords a strong argument in favour of assigning ,eremopteris artemisaefolia to the ,pteridosperms4 #ahbf4 ,sphenopteris artemisaefolia ,steinberg1 ,flor4 ,vorwelt1 ,fasc4 iv4 p4 #ae1 ,pl4 lvi4 fig4 #a4 #ahcc4 ,sphenopteris crithmifolia ,lindley and ,hutton1 ,foss4 ,flor4 ,vol4 i4 ,pl4 xlvi4 #ahcc4 ,cardiocarpon acutum1 ,ibid4 ,pl4 lxxvi4 #ahfi4 ,eremopteris artemisaefolia ,schimper1 ,trait4 ,pal4 ,vg4 ,vol4 i4 p4 #daf4 #aiad4 ,samaropsis acuta ,kidston1 ,trans4 ,r4 ,soc4 ,edinb4 ,vol4 l4 ,pt i4 p4 #aef4 ,the large compound fronds of this species#ddi are characterised by the regular dichotomy of the main branches1 a feature frequently met with in ,palaeozoic fern-like leaves3 the cuneate or oval-cuneiform pinnules 7fig4 #ddc1 ,a1 ,c7 vary considerably in breadth from the typical cuneate type of segment as figured by ,brongniart#dej to narrow1 almost linear1 leaflets like those of ,sphenopteris crithmifolia4 ,several spreading veins traverse the lamina4 ,lindley and ,hutton1 while admitting a very close resemblance between their species and ,s4 artemisaefolia1 adopted a distinctive name4 ,the only evidence so far obtained as to the stem of the plant is furnished by some specimens in the ,hutton collection 7,newcastle-upon-,tyne7 one of which shows a piece of rhizome bearing several petioles 7fig4 #ddc1 ,b73 there are no pinnules attached to the rachises but some occur in close association4 ,brongniart noticed the frequent association of ,eremopteris fronds with small seeds1 but he regarded it as accidental4 ,dr ,kidston#dea has recently drawn attention to a note by ,prof4 ,duns published in #ahgb on the juxtaposition of seeds and fronds1 and ,mr ,howse#deb in his ,catalogue of the ,hutton plants considers that the seeds were borne on the ,eremopteris leaves2 in his synonymy of ,e4 artemisaefolia he includes ,cardiocarpon acutum ,lind4 and ,hutt4 as the #8spore-cases or sporangia4' ,the ,eremopteris seeds are of the platyspermic 7,samaropsis7 type1 broadly oval and about #g mm4 long with an obtuse base and two slightly divergent acute processes at the apex 7fig4 #ddd74 ,some specimens in ,dr ,kidston's collection from the ,lower ,coal ,measures of ,midlothian1 which were associated with ,eremopteris fronds1 are preserved as mummified cuticular membranes and on microscopical examination they show clearly the presence of a pollen-chamber4 ,the seeds are of the ,samaropsis type4 ,the drawings reproduced in fig4 #ddd were made for me by ,dr ,kidston from two specimens1 in his collection1 of exceptionally well-preserved seeds from ,midlothian3 the seeds of this species vary considerably in size and form2 some are almost orbicular and show no distinction between nucule and border 7fig4 #ddd1 ,a7 while in others 7,b7 the impression of the flattened and longitudinally striated sarcotesta is clearly distinguished4 ,kidston is of opinion that in younger seeds there is a single apical point replaced in a later stage of development by two cusps1 as seen in figs4 ,a and ,b1 formed by the opening of the micropylar tube4 ,a ridge in the middle of the flattened surface indicates the position of the vascular bundles in the principal plane as in ,cardiocarpus4 ,the fully developed seeds are #h-i mm4 long4 ,the correlation of the seeds represented in figs4 #ddc and #ddd with ,eremopteris fronds furnishes an additional illustration of the impossibility of trusting to external form as a criterion of affinity1 for it is known that seeds of the ,samaropsis type were produced by ,pteridosperms with foliage represented by ,eremopteris artemisaefolia and ,pecopteris ,pluckeneti1 also by some members of the ,cordaitales 7e4g4 fig4 #dhj74 ,dr ,arber#dec has recently proposed a new generic name ,cornucarpus for ,cardiocarpon acutum1 but the drawings that he gives of seeds from the ,kent coal-field referred to this species suggest a type distinct from that of ,lindley and ,hutton4 ,in the absence of specimens showing actual attachment it is impossible to say how the seeds were borne1 but the analogy of ,wardia fertilis and ,pecopteris ,pluckeneti lends support to the view that the seeds were attached to pinnules with a reduced lamina4 ,eremopteris artemisaefolia occurs in the ,lower and ,middle ,coal ,measures of ,england3 a species recorded by ,kidston from the ,calciferous sandstone of ,scotland as ,e4 ,macconochii#ded is now believed by that author to be generically distinct#dee4 ,with the exception of the unsatisfactory specimen reproduced in fig4 #ddc1 ,b1 we have no information with regard to the habit of the stem to which the ,eremopteris leaves were attached4 ,illustration3 ,fig4 #ddc4 ,eremopteris artemisaefolia4 ,a1 part of a frond with associated seeds of ,samaropsis acuta2 ,b1 rhizome with fragments of fronds2 ,c1 pinnule4 7,drawn by ,mr ,l4 ,d4 ,sayers from specimens in the ,hutton ,collection1 ,newcastle4 ,a1 ,b1 nat4 size47 ,illustration3 ,fig4 #ddd4 ,samaropsis acuta4 7,from drawings by ,dr ,kidston of specimens in his collection1 #cdge 7,a71 #ccaf 7,b72 #b47 ,illustration3 ,fig4 #dde4 ,wardia fertilis 7,white74 ,a1 sterile portion of frond2 ,b1 ,d1 enlarged pinnules2 ,c1 seed4 7,after ,white4 ,a1 ca1 nat4 size2 ,b-,d1 #b47 ,,wardia4 ,white4 ,wardia fertilis 7,white74 ,another example of a fern-like frond bearing seeds is afforded by specimens from the ,lower ,pottsville series of ,virginia 7correlated with the ,millstone grit of ,british geologists7 described by ,mr ,david ,white#def as ,aneimites 7,wardia7 fertilis4 ,the compound fronds usually referred to the genus ,adiantides or ,adiantites#deg are characterised by cuneate pinnules with a thin lamina and forked1 slightly divergent veins 7fig4 #dde1 ,a1 ,d74 ,white discards the name ,adiantides in favour of ,dawson's genus ,aneimites on the ground that ,goeppert#deh1 who instituted the former term1 applied it in the first instance to leaves of ,ginkgo which he identified as simple ,fern fronds4 ,in spite of this misapplication of the name it has been constantly used and is well established4 ,the discovery of seeds is1 however1 a reason for the adoption of a new generic name1 and as ,white proposed ,wardia for the seeds it may appropriately be extended to the fronds in place of the provisional term ,aneimites4 ,the seeds which occur at the apices of slender pedicels on pinnae bearing relatively small pinnules with a reduced lamina 7fig4 #dde1 ,b1 ,c7 are rhomboidal in shape1 #de mm4 long and #be mm4 broad4 ,the bilaterally symmetrical seeds were probably enclosed1 as ,white suggests1 in a fleshy integument which on pressure became laterally extended as a wing-like border4 ,in some of the seeds there is an indication of a #8slight collapse within the apex of the nutlet1' which may mean the presence of a pollen-chamber2 but while the preservation is too imperfect to afford any decisive evidence as to anatomical features1 there is no reason to doubt the conclusion as to the seed-nature of the organs described by ,white4 ,nothing is known of the stem1 though the opinion may be hazarded that ,wardia is a member of the ,medulloseae4 ,adiantites bellidulus ,heer and ,lagenospermum ,arberi ,nathorst4 ,reference is made to the genus ,lagenospermum in the account of ,lagenostoma#dei4 ,the species ,lagenospermum ,arberi has recently been founded by ,dr ,nathorst#dfj on some seeds obtained from ,lower ,carboniferous rocks in ,spitzbergen3 a brief description is intercalated here because it is probable that they were borne on fronds of the ,adiantites type similar to those on which ,white found the seeds described by him as ,wardia4 ,the seeds of ,l4 ,arberi1 #ad-ah #e mm41 are spindle-shaped with an obtuse apex and longitudinally ribbed with a stalk at least #g mm4 long4 ,nathorst considers that a cupule was probably present3 the specimens do not convey the impression of naked seeds and in some examples there are indications of an investing envelope1 though this may be the result of tearing of the testa4 ,nathorst regards the ,spitzbergen seeds as probably specifically identical with a specimen described by ,schmalhausen#dfa from ,carboniferous rocks in the ,urals as ,rhabdocarpus orientalis ,eich41 a species which agrees closely with ,lagenospermum nitidulum as described by ,heer#dfb 7under the name ,carpolithes nitidulus7 and ,nathorst#dfc from ,spitzbergen4 ,it is also possible that ,kidston's ,rhabdocarpus elongatus#dfd1 from the ,lanarkshire coal-field and elsewhere1 recently transferred by ,arber#dfe to ,platyspermum1 is an example of the same species4 ,the chief interest of ,lagenospermum lies in the fact1 assuming ,nathorst's correlation of the seeds with ,adiantites bellidulus ,heer to be correct1 that it is a typical radiospermic seed1 while ,wardia1 borne on foliage of the same general type1 is an equally typical platyspermic seed4 ,,chapter ,,xxxii4 ,,cycadofilices4 ,in this chapter are included several types represented by stems1 but which in the absence of definite information with regard to the reproductive organs cannot be assigned to the ,pteridosperms4 ,,megaloxyleae4 ,megaloxylon4 ,seward4 ,this genus is represented by a single species founded on a piece of stem from the ,lower ,coal ,measures of ,lancashire discovered in the ,binney ,collection in the ,sedgwick ,museum1 ,cambridge#dff4 ,nothing is known as to the leaves1 reproductive organs1 or roots4 ,the type-specimen consists exclusively of primary and secondary xylem4 ,megaloxylon ,scotti ,seward4 ,the type-specimen1 reproduced natural size in fig4 #ddf1 ,a1 ,b1 consists of a fragment of stem which at first sight bears a close resemblance to ,cordaites1 but the apparent pith1 #ai cm4 in diameter1 is the primary xylem of the stele and is enclosed by an incomplete cylinder of secondary xylem #b cm4 broad4 ,the distinction between the lighter primary xylem and the darker secondary cylinder is especially well marked in the longitudinal section 7fig4 #ddf1 ,b74 ,the central region1 shown on a larger scale in fig4 #ddg1 is occupied by groups of tracheids varying in size and shape associated with thin-walled parenchyma3 the latter is represented by lighter patches in the section4 ,the majority of the tracheids are characterised by their great breadth--in some cases #d mm4--and their isodiametric or even horizontally elongated and flattened form4 ,some of these large metaxylem elements are seen in longitudinal section at m in fig4 #ddh where the shrinkage and partial decay of the parenchymatous tissue have resulted in the separation of transverse bands of xylem simulating the discoid pith of a ,cordaites4 ,the walls of these tracheal cells are covered with multiseriate pits4 ,with the short and sometimes flattened xylem elements occur others of greater length1 but these are chiefly met with in the more peripheral part of the central region where some of the tracheids are much narrower and have the form of ordinary water-conducting elements4 ,on one side of the primary xylem in fig4 #ddg an oval and more compact group of narrow and longer tracheids is seen at lt2 this is a leaf-trace about to enter the secondary-xylem cylinder on its outward course4 ,the same leaf-trace is shown at lt in fig4 #ddf1 ,b2 as it descends the trace becomes less distinct and its elongated elements gradually merge into the general mass of metaxylem4 ,a portion of this leaf-trace is seen in fig4 #ddh1 ,b1 lt1 close to the inner edge of the secondary xylem1 x1 and abutting internally on the contracted tissue1 m1 which consists mainly of large and short tracheae with remains of associated parenchyma4 ,the trace includes some conjunctive parenchyma interspersed with the tracheids3 on its outer surface1 that is on the abaxial edge of the ovate xylem strand as shown at lt in fig4 #ddg1 there are six external protoxylem strands4 ,in the peripheral region of the primary xylem of the section reproduced in fig4 #ddg there are several more or less well-defined leaf-traces1 e4g4 lt1 lt2 these differ from that seen at lt in their greater tangential breadth and in the less compact arrangement of the tracheids4 ,as each trace is followed downwards in the primary region of the stele it tends to become broader1 especially in a tangential direction2 the spiral protoxylem strands are more widely separated 7fig4 #ddh1 ,a1 px7 and the elongated and comparatively narrow tracheids as they spread out fan-wise are reduced in length1 finally passing over into the broad and short reticulately pitted cells4 ,each leaf-trace can be followed through approximately four internodes before its individuality is lost in the general mass of metaxylem4 ,the disposition of the peripheral traces is such as to justify the conclusion that the phyllotaxis of the stem is 4#dfg ,illustration3 ,fig4 #ddf4 ,megaloxylon ,scotti4 ,a1 ,b4 ,transverse and longitudinal sections4 x1 x1 primary and secondary xylem2 lt1 leaf-traces4 ,nat4 size4 ,c4 ,secondary xylem4 ,illustration3 ,fig4 #ddg4 ,megaloxylon ,scotti4 ,transverse section of the primary portion of the stele with leaf-traces1 lt1 and the inner edge of the secondary xylem4 ,illustration3 ,fig4 #ddh4 ,megaloxylon ,scotti4 ,a1 transverse section at the junction of the primary and secondary tissues2 ,b1 longitudinal section showing the inner edge of the secondary xylem1 x1 a leaf-trace1 lt1 and the metaxylem1 m4 ,the secondary xylem 7fig4 #ddf1 ,c7 resembles that of ,lyginopteris and ,heterangium though it is less parenchymatous4 ,the medullary rays are numerous and vary in breadth from #a to #e cells1 while the tracheids1 with multiseriate bordered pits on their radial walls1 form bands #a to #h elements in breadth4 ,there are no regular rings of growth but occasional arcs of narrow tracheids interfere slightly with the otherwise uniform structure of the wood4 ,a leaf-trace in its oblique outward course through the wood becomes completely enclosed by a cylinder of secondary xylem and thus appears to be concentric4 ,owing to the absence of any tissue external to the secondary xylem of the stem1 statements as to the subsequent behaviour of the leaf-traces on emerging from the stele are purely hypothetical4 ,it is1 however1 not improbable that each concentric trace lost its secondary tissue and broke up into several collateral strands1 a suggestion based on the behaviour of the leaf-traces in ,medullosa anglica4 ,the most striking characteristics of ,megaloxylon are3 7i7 the structure of the primary xylem1 particularly the unusual form of the majority of the metaxylem tracheids1 a form obviously correlated with storage rather than with conduction of water2 7ii7 the gradual spreading of the leaf-traces and their absorption as they descend into the main mass of the xylem2 7iii7 the exarch structure of the primary xylem4 ,confining our attention to the primary region of the stele2 a comparison is at once suggested with ,heterangium4 ,in ,megaloxylon the peculiarities are the substitution of the large storage-tracheids for the normal xylem-elements2 the greater irregularity in the groups of metaxylem2 and an exarch instead of a mesarch structure4 ,in these last features the primary xylem agrees with that of recent species of the ,schizaeaceous ,fern ,lygodium and the external protoxylem is a character shared with ,rhetinangium4 ,the occurrence of short tracheids similar to those of ,megaloxylon in the inner portion of the stele of the ,osmundaceous ,fern ,zalesskya gracilis 7,eich47#dfh may be quoted as an example of parallel modification but1 as ,scott#dfi points out1 the resemblance has no phylogenetic significance4 ,the secondary xylem though less parenchymatous than in recent ,cycads agrees more closely with the manoxylic than with the pycnoxylic type4 ,megaloxylon affords an interesting example of a combination of primary stelar anatomical features1 comparable in the exarch position of the protoxylem with the stele of ,lygodium1 and secondary wood similar to that of ,lyginopteris and ,heterangium4 ,the large metaxylem tracheids may be regarded as derivatives of elements which in some ancestral type were structurally fitted for the rle of water-transport and made up the xylem of a ,lygodium-like stele with little or no secondary xylem4 ,as the cambial activity increased and centrifugal xylem became a prominent feature1 usurping the function of the centripetal xylem1 the latter became modified and fitted for a new service4 ,,rhetinangieae4 ,rhetinangium4 ,gordon4 ,rhetinangium ,arberi ,gordon4 ,the stem on which this genus is founded was discovered by ,dr ,gordon#dgj in the ,calciferous ,sandstone series of ,pettycur3 a specimen collected by ,dr ,kidston in ,berwickshire may be specifically identical with the ,pettycur plant4 ,we know nothing of the leaves or reproductive organs of ,rhetinangium4 ,the stem1 approximately #b cm4 in diameter1 was probably cylindrical2 it possesses a single stele consisting mainly of a central primary region occupied by anastomosing groups of tracheids1 #acj-aej in diameter1 embedded in parenchyma containing numerous secretory sacs and ducts4 ,in the peripheral region of the stele the groups of tracheids consist of narrower elements characterised by exarch protoxylem4 ,each peripheral group forms the base of a wedge of secondary xylem 7fig4 #dej1 x71 the primary medullary rays being in direct connexion with some of the parenchyma of the primary xylem4 ,the secondary tracheids1 #de-he in diameter1 have multiseriate bordered pits on their radial walls and the rays are broad and deep as in ,heterangium and ,lyginopteris4 ,with the exception of the external position of the protoxylem1 the stele of ,rhetinangium is practically identical with that of ,heterangium1 though in ,rhetinangium the primary tracheids form larger and fewer groups4 ,the inner cortex is composed of thin-walled cells with many secretory sacs3 there are no stereome elements4 ,in the outer cortex 7fig4 #ddi1 cr7 radially disposed bands of stereome form a reticulum with narrow and very long meshes like that of ,medullosan petioles4 ,the recently recorded occurrence of polydesmic petioles#dga in ,heterangium is of special interest from the point of view of the comparison of that genus with ,rhetinangium and the ,medulloseae4 ,the very broad decurrent petiole-bases are a striking feature1 the major diameter of the pulvinus-like base of the leaf-stalk exceeding that of the stem 7fig4 #ddi1 p74 ,several xylem-strands from the peripheral region of the primary xylem go to form a single leaf-trace3 these ,u-shaped strands of xylem destined for a leaf are connected laterally by parenchyma and form an irregularly corrugated band4 ,fig4 #dej shows a petiole-trace still enclosed on each side by the secondary xylem cylinder x4 ,illustration3 ,fig4 #ddi4 ,rhetinangium ,arberi ,gord4 ,transverse section of stem with large leaf-base2 cr1 outer cortex of stem2 p1 petiole4 7,after ,gordon2 #a47 ,there are several protoxylem groups in a leaf-trace1 one on the outer face of each xylem-strand4 ,in the petiole the xylem groups are more intimately connected and the trace has the form of a flat band with abaxial protoxylem4 ,there is no indication that a leaf-trace undergoes division into separate strands4 ,the roots are described as tetrarch with well-developed secondary xylem4 ,illustration3 ,fig4 #dej4 ,transverse section of leaf-trace of ,rhetinangium ,arberi showing the exarch structure2 x1 secondary xylem4 7,after ,gordon47 ,the primary xylem of ,rhetinangium agrees in its exarch structure with the ,palaeozoic genera ,sutcliffia1 ,megaloxylon and ,stenomyelon1 also with ,lygodium and some other recent ,ferns3 the secondary wood is of the manoxylic type like that of ,lyginopteris1 ,heterangium and other genera4 ,in the general structure of the stele ,rhetinangium agrees with ,sutcliffia and1 except in the exarch structure of the primary xylem1 with the steles of ,heterangium and ,medullosa anglica#dgb2 but the structure and origin of the leaf-traces are characters which mark it off from ,sutcliffia4 ,the sclerenchymatous bands in the inner cortex of ,heterangium are unrepresented in ,rhetinangium1 and in the latter genus the abundance of secretory sacs and ducts is a characteristic feature1 moreover in ,rhetinangium1 the leaf-trace consists of several groups of primary xylem-elements4 ,dr ,gordon regards ,megaloxylon as the type which comes nearest to ,rhetinangium2 but the differences in the structure of the secondary wood and the marked contrast between the leaf-traces are too pronounced to justify a preference for ,megaloxylon over ,heterangium in the order of affinity4 ,gordon considers that the undivided leaf-trace of ,rhetinangium may represent a form transitional between the simple leaf-trace of ,lyginopteris and the much divided type in ,medullosa4 ,the external position of the protoxylem is a character to which too much weight may easily be attached3 the difference in position between the protoxylem of ,rhetinangium and ,heterangium is in some examples of the latter genus hardly perceptible4 ,kubart#dgc speaks of the stele of his species ,heterangium ,sturi as being almost exarch4 ,the inconstancy in the position of the protoxylem in the xylem of ,osmundaceous stems and in the primary bundles of ,eristophyton and other ,palaeozoic genera is worthy of consideration in this connexion4 ,illustration3 ,fig4 #dea4 ,stenomyelon tuedianum ,kidst4 ,transverse section of stem4 ,the black patches represent leaf-traces4 7,after ,kidston2 #a47 ,,stenomyeleae4 ,stenomyelon4 ,kidston4 ,stenomyelon tuedianum ,kidston4 ,the specimens on which this monotypic genus is founded#dgd were obtained from the ,lower ,carboniferous rocks 7,calciferous ,sandstone series7 at ,norham ,bridge1 ,berwickshire1 ,scotland4 ,they consist of petrified pieces of a flattened stem1 a fragment of a rachis and portions of laminae3 there is no evidence as to the nature of the reproductive organs4 ,the original form of the stem is obscured by the destruction of a considerable part of the cortex and the consequent flattening of the whole with the production of wing-like extensions of the imperfectly preserved tissues enclosing the almost cylindrical stele 7figs4 #dea1 #deb74 ,the stele consists of a bluntly triangular core of primary xylem1 #c-d mm4 in diameter1 composed almost entirely of reticulately pitted tracheids reaching a diameter of #afj3 a few parenchymatous cells occur in the peripheral region and a band of parenchyma extends from the middle of each of the three sides of the xylem to the centre of the stele1 thus dividing the primary conducting tissue into three groups which are the expression of a phyllotaxis of 4 ,the tracheids near the outer face of each xylem-group are narrower than the others and have scalariform pitting4 ,the secondary xylem first appears along the slightly concave sides of the primary stele1 eventually enclosing the whole3 it consists of tracheids with multiseriate pits on the radial walls and numerous deep medullary rays #a-f cells broad4 ,no phloem is preserved though it is probable that a narrow band was originally present4 ,a characteristic feature is afforded by a zone of thick-walled cells1 regarded as periderm1 encircling the stele and formed by a deep-seated phellogen4 ,on the outer face of this band there are projecting bosses1 and similar sclerous nests are scattered in the cortex4 ,the outer cortex has a ,sparganum#dge type of hypoderm1 that is long vertical strands of fibres alternating with parenchyma4 ,the leaf-traces are formed from the blunt angles of the primary xylem2 an angle becomes nipped off as a more or less cylindrical strand enclosed by a zone of secondary tracheids which is very narrow on the adaxial side 7fig4 #deb74 ,protoxylem was recognised only in the leaf-traces and not in the rest of the stele4 ,a pair of protoxylem strands occurs on the outer edge of a prominent angle of xylem before it becomes detached from the stele1 and these form a single strand at a lower level4 ,as a leaf-trace passes outwards1 the exarch xylem strand becomes mesarch and there is a single protoxylem group except at a point near the bifurcation of a trace4 ,in its passage through the cortex a leaf-trace divides repeatedly1 the secondary xylem on the outer face of each strand being retained for a considerable time4 ,our meagre knowledge of the nature of the leaves is based on incomplete fragments found in association with the stem4 ,the leaf is believed to have been simple and characterised by a thick lamina with a hypodermal zone of sclerous strands and several vascular bundles4 ,illustration3 ,fig4 #deb4 ,stenomyelon tuedianum4 ,transverse section of stele4 7,after ,kidston2 #g47 ,as ,kidston and ,gwynne-,vaughan#dgf remark1 ,stenomyelon is a very distinct type2 while resembling ,sutcliffia in some respects it differs from that genus not only in the structure of the primary stele but in the absence of the system of meristeles which form so characteristic a feature of the latter genus4 ,,cycadoxyleae4 ,cycadoxylon4 ,renault4 ,this generic term#dgg is applied to a few types of ,permian and ,upper ,carboniferous stems possessing a vascular cylinder1 which may reach a considerable breadth1 of secondary centrifugally developed xylem and phloem enclosing a large pith containing either a narrow1 peripherally placed1 and more or less continuous cylinder of inversely orientated conducting tissue or scattered bands of centripetal xylem and phloem4 ,the secondary xylem is manoxylic1 while the internal vascular tissue recalls that of ,ptychoxylon and to a less extent the inverted arcs that are rarely met with in ,lyginopteris stems4 ,a brief diagnosis of two species may serve to illustrate the genus3 a third species is included in ,cycadoxylon1 but it is founded on material too incomplete to admit of satisfactory diagnosis4 ,cycadoxylon ,fremyi ,renault4 ,this ,permian species#dgh is represented by a piece of stem #b-be cm4 in diameter 7fig4 #dec1 ,b7 characterised by 7i7 a fairly broad parenchymatous cortex with secretory canals and several hypodermal nests of sclerous tissue1 7ii7 a cylinder of secondary xylem and phloem nearly the whole of which is centrifugal1 7iii7 a large pith containing several scattered narrower bands or arcs of centripetally developed xylem and phloem4 ,the tracheids1 with #d-f series of hexagonal pits1 form radially disposed rows1 #a-d elements broad1 separated by broad and deep medullary rays4 ,renault does not mention the occurrence of any primary xylem as distinct from the secondary centrifugal xylem1 but in a section which ,i examined some years ago in his laboratory there appeared to be a group of primary tracheids4 ,there are no anastomoses between the main cylinder and the internal bands of inversely orientated tissue4 ,cycadoxylon robustum 7,seward74 ,this species#dgi is based on a piece of stem from the ,lower ,coal ,measures of ,lancashire first described by ,williamson and identified as an unusually large example of ,lyginopteris4 ,williamson and ,scott1 while recognising certain features in addition to the large size of the stem1 which must have reached #ad cm4 in diameter1 expressed the view that #8there is a presumption that it really belonged to a ,lyginodendron1 or to some plant of the same type of structure4' ,the examination of additional material led me to adopt the name ,lyginodendron robustum1 though ,i suggested that possibly ,cycadoxylon might be the more appropriate genus4 ,subsequently ,scott#dhj proposed the substitution of ,cycadoxylon for ,lyginodendron4 ,the type-specimen consists of secondary xylem agreeing closely in structure with ,lyginopteris and recent ,cycads3 the pith1 #bi cm4 in breadth1 is incompletely preserved2 there is a narrow band of centripetal xylem#dha at the periphery of the perimedullary region and close to the inner face of the main mass of wood 7fig4 #dec1 ,c2 the black line marks the position of the centripetal xylem74 ,nests of sclerous tissue and secretory canals are scattered in the medullary parenchyma and deeper in this region are arcs of secondary parenchyma1 possibly periderm4 ,in places the centripetal and centrifugal xylem are in contact and occasionally the tapered ends of the rows of centrifugal tracheids merge into groups of primary xylem elements4 ,the preservation in the central region is far from complete1 and although the occurrence of primary xylem groups is probable it cannot be said to be positively established4 ,at the inner edge of the centrifugal xylem and in tangential longitudinal sections a few leaf-traces are seen1 but nothing is known as to the nature of the leaf-traces in their course beyond the stele nor have we any data with regard to the leaves or reproductive organs4 ,this older species differs from ,cycadoxylon ,fremyi in the limitation of the centripetal xylem to the outer portion of the pith and in the presence of sclerous nests in the medullary region1 though the latter character is probably of no great taxonomic value4 ,cycadoxylon robustum approaches more closely to ,lyginopteris1 and although the differences are sufficient to justify a distinctive generic name1 there can be little doubt as to a fairly intimate relationship between this type of ,cycadoxylon and ,lyginopteris4 ,ptychoxylon4 ,renault4 ,ptychoxylon#dhb ,levyi ,renault4 ,like many ,palaeozoic genera founded on anatomical features1 ,ptychoxylon#dhc is represented only by stems1 our knowledge of the leaves being confined to the leaf-traces in the stem which appears to have a phyllotaxis of 4 ,the stem of this ,permian species has a diameter of #e-f cm43 the comparatively broad cortex contains numerous secretory canals1 but in place of hypodermal strands of stereome there is a superficial periderm4 ,the vascular tissue1 consisting of secondary xylem and phloem1 assumes different patterns at different levels4 ,there is an outer vascular cylinder of centrifugally developed xylem and phloem2 the xylem is manoxylic and the tracheids have #c-e rows of bordered pits on the radial walls4 ,at intervals the continuity of the main stele is broken by the formation of leaf-gaps and before one gap is repaired a second may be produced1 thus converting the cylinder into two crescentic and infolded bands 7fig4 #dec1 ,a74 ,a striking character is the occurrence in the large parenchymatous central region of internal vascular bands or arcs varying in size and number at different levels and composed of centripetally developed secondary xylem and phloem4 ,these internal bands differ from the outer and broader cylinder both in their inverse orientation and their limited vertical range4 ,the connexion between the inner and outer vascular tissue and the alteration in plan of the conducting tissue at different levels are illustrated by fig4 #dec1 #a-d1 simplified from some of ,renault's figures of successive sections through a vertical distance of #d-e cm4 ,in section #a the main cylinder is continuous except for a small gap where a leaf-trace is about to be given off3 there are three internal vascular bands similar in structure to the outer stele but inversely orientated4 ,at a higher level 7section #b7 the leaf-gap is larger and in it is a double leaf-trace of two collateral strands consisting of primary centripetal xylem and a fan-like group of secondary xylem and phloem4 ,the free edges of the outer stele of section #a have curved inwards and united with the two lateral medullary bands1 while the lower internal band of section #a has increased in extent and forms a discontinuous arc with the upper portions enclosed by the loops formed by the infolded ends of the outer vascular tissue4 ,in section #c a second leaf-gap has been formed in the outer stele and its invaginated ends have fused with the internal bands4 ,in section #d the first leaf-gap is closed and the invaginated bands of section #c have broken up into an irregular circle of shorter bands4 ,the section reproduced in fig4 #dec1 ,a1 shows the main cylinder in the form of two curved and flattened loops1 each composed partly of the centrifugally developed xylem and phloem of the main stele and in part of the inversely orientated tissue of the inner bands4 ,at a lower level the two bands b1 b1 will become detached as the upper leaf-gap is closed and form part of an inner cylinder like the discontinuous ellipse formed by the two bands c4 ,the section of a branch-stele is seen at a4 ,illustration3 ,fig4 #dec4 ,a4 ,ptychoxylon ,levyi2 transverse section of stem2 a1 stele of branch4 7,after ,renault47 ,b4 ,cycadoxylon ,fremyi2 transverse section of stem4 7,after ,renault47 ,c4 ,cycadoxylon robustum2 centre of stem4 #a-d1 diagrams of sections of the stem of ,ptychoxylon at different levels4 7,simplified from ,renault47 ,ptychoxylon differs considerably from ,medullosa1 which ,renault included in the ,cycadoxyleae1 in the plan of the vascular system3 there is nothing corresponding to the #8partial pith' or primary region which forms the central portion of the plate- and snake-rings in ,medullosa4 ,the double leaf-trace and the absence of the ,medullosa type of hypoderm are other distinguishing features4 ,the paired leaf-bundles suggest comparison with ,lyginopteris among other genera and1 as ,scott#dhd points out1 the internal arcs of inversely orientated tissue which sometimes occur in the peripheral region of the pith of ,lyginopteris 7fig4 #dje1 ,c1 c7 behave like the internal bands of ,ptychoxylon in occasionally joining the main cylinder at a leaf-gap2 but the differences outweigh the resemblances4 ,as regards the general arrangement of the vascular tissue in two irregular concentric circles and their connexions with one another1 but not in the structure of the xylem and phloem1 there is a similarity between this genus and such a ,fern as ,matonia4 ,in the varying patterns formed by the vascular system at different levels in the stem ,ptychoxylon resembles the ,ferns ,polypodium quercifolium and ,p4 heracleum#dhe4 ,,calamopityeae4 ,calamopitys4 ,unger4 ,in #ahef ,unger#dhf described several fragmentary petrifactions from ,thuringian strata of ,upper ,devonian age1 the majority of which he referred to the ,calamarieae and the ,rhachiopterideae4 ,in an earlier publication#dhg he gave a list of species including two families1 the ,haplocalameae and the ,calamoxyleae1 assigned by him to the group ,calamarieae3 in the ,haplocalameae he placed the new genera ,kalymma1 ,calamosyrix1 ,calamopteris1 and ,haplocalamus4 ,these were subsequently examined by ,graf ,solms-,laubach and identified as portions of petioles1 for the most part belonging to unknown stems4 ,in his second family1 the ,calamoxyleae1 ,unger included the single genus ,calamopitys represented by the type-species ,c4 ,saturni4 ,the type-specimens have been thoroughly investigated by ,solms-,laubach#dhh who instituted the family-name ,calamopityeae and recognised a close anatomical affinity between ,calamopitys and ,lyginopteris1 a conclusion which led to the incorporation of ,unger's genus in the ,pteridosperms4 ,further data have been supplied by ,zalessky#dhi and1 more recently1 by ,scott and ,jeffrey#dij who have recognised ,calamopitys in ,lower ,carboniferous beds in ,kentucky4 ,calamopitys ,saturni ,unger4 ,our knowledge of this and other species is confined to stems and petioles4 ,one of the largest examples of the species is a piece of stem with a diameter of #ae cm43 the single stele consists of a parenchymatous pith enclosed by secondary xylem made up of tracheids with #d-h rows of bordered pits and medullary rays more than one cell broad and of considerable depth4 ,between the inner edge of the wood and the pith are groups of primary xylem 7fig4 #ded1 ,b1 x7 which1 like those in ,lyginopteris1 constitute the leaf-traces3 each has a single internal protoxylem strand 7fig4 #dee1 ,b74 ,the comparatively wide cortex consists of parenchyma with a hypoderm of the ,sparganum type4 ,each primary xylem-strand passes out as a single leaf-trace through the secondary xylem and on emerging divides into two as in ,lyginopteris3 these branch in the cortex and the two are replaced by six in the leaf-base 7fig4 #ded1 ,b-,d74 ,as seen in figs4 #ded1 ,c1 #dee1 ,a1 the boundary between the stem proper and the decurrent leaf-base is marked by a line of stereome strands4 ,the petioles of ,calamopitys ,saturni agree generally in structure with the imperfect specimens on which ,unger founded his genus ,kalymma#dia1 so named in reference to the structure of the hypodermal zone4 ,a specimen described by ,solms-,laubach as a ,kalymma petiole occurs in organic connexion with a stem of ,calamopitys 7fig4 #ded1 ,c3 a detached petiole is shown in fig4 #ded1 ,d74 ,the identification by ,white#dib of this attached petiole with ,unger's ,k4 grandis has been confirmed by ,scott and ,jeffrey4 ,a fuller account of ,kalymma 7fig4 #def7 is given on a later page1 as the petioles so named belong to more than one species of stem4 ,illustration3 ,fig4 #ded4 ,calamopitys ,saturni4 ,b1 stem with leaf-base2 x1 primary xylem and pith2 black patches represent leaf-traces2 ,c1 stem with two leaf-bases2 ,d1 section of petiole4 7,after ,solms-,laubach47 ,illustration3 ,fig4 #dee4 ,calamopitys ,saturni4 ,a1 stem with leaf-bases2 #e4 ,b1 stele showing leaf-trace after emerging from the secondary xylem2 #af4 7,after ,zalessky47 ,in ,calamopitys ,saturni we have a plant agreeing with ,lyginopteris in the possession of secondary xylem of the manoxylic type and in the structure of the common primary bundles1 while it is distinguished from ,lyginopteris by the greater number and by the structure of the bundles in the axis of the leaf4 ,calamopitys annularis 7,unger7#dic4 ,this species1 originally assigned to the genus ,stigmaria1 has a more strongly developed primary vascular system and there is a more decided tendency towards the formation of a continuous zone of primary xylem on the inner edge of the secondary wood2 but where the protoxylem tracheids occur the metaxylem elements form definite strands1 like those of ,c4 ,saturni4 ,it has been pointed out by ,scott and ,jeffrey that there is some evidence of the occurrence of tracheids in the parenchymatous pith of this species1 an important feature distinguishing it from ,c4 ,saturni and connecting it with ,c4 americana4 ,information with regard to the behaviour of the leaf-traces is far from complete1 but there are indications that each trace divides into two before emerging from the secondary xylem#did4 ,the leaf-traces in the cortex are concentric as in ,c4 ,saturni4 ,calamopitys americana ,scott and ,jeffrey4 ,this ,lower ,carboniferous species#die from the ,waverley shales of ,kentucky is represented by portions of stems and leaf-bases and detached petioles4 ,the secondary wood consists of tracheids1 #cj-fj in diameter1 with deep and broad rays2 the small pits on the tracheids form #e-f alternating series4 ,phloem and cambium are very imperfectly preserved4 ,the outer cortex is of the same type as in other species4 ,at the inner edge of the secondary xylem there is a ring of primary xylem strands of mesarch structure composed of rather larger tracheids1 #hj-abj in diameter1 separated from one another by narrow strips of parenchyma4 ,so far the vascular tissue agrees with that of ,c4 annularis4 ,in the ,american species the axial region is not a parenchymatous pith but a protostele1 consisting of parenchyma and a larger or smaller number of tracheal groups1 the number being less in stems with a larger central region4 ,the peripheral strands alone are concerned with the emission of leaf-traces1 as in ,heterangium4 ,each primary xylem strand divides into two as it leaves the perimedullary zone and passes through the secondary xylem as two bundles1 each being accompanied by an arc of secondary tracheids which1 in the cortical region1 completely surrounds the primary elements4 ,at a later stage the single protoxylem of each trace divides into two and before entering the leaf-base there is a further division4 ,in some specimens leaf-bases of the ,kalymma type were found attached to the stem4 ,the occurrence of tracheids in the axial region is a distinguishing feature and suggests a comparison with ,heterangium1 while ,c4 ,saturni agrees more closely with ,lyginopteris2 the species ,c4 annularis would appear1 from the recent observations of ,scott and ,jeffrey1 to occupy an intermediate position4 ,calamopitys1 as the generic designation is here employed1 is confined to central ,germany and ,kentucky and occurs in ,upper ,devonian and ,lower ,carboniferous strata4 ,there is1 however1 some doubt as to the exact geological horizon of the rocks in both countries though in neither case is there any question of an horizon higher than ,lower ,carboniferous4 ,certain specimens from the ,lower ,carboniferous of ,scotland described by ,scott#dif as species of ,calamopitys have been made by ,zalessky the type of a new genus1 ,eristophyton1 and are dealt with under that name4 ,kalymma4 ,unger4 ,kalymma grandis 7petiole of ,calamopitys74 ,under the generic name ,kalymma ,unger described specimens from ,thuringia of ,upper ,devonian age which he assigned to two species1 ,k4 grandis and ,k4 striatum4 ,solms-,laubach has shown that ,kalymma is not an independent stem as ,unger believed but a petiole of ,calamopitys1 and this has been confirmed by ,scott and ,jeffrey who found a leaf-base with the ,kalymma type of structure in connexion with a piece of ,calamopitys stem1 probably ,c4 americana4 ,an examination of a section 7#bc cm4 broad7 of ,unger's ,k4 grandis in the collection of the ,geological ,survey enables me to confirm the conclusions recently published by ,scott and ,jeffrey4 ,the best specimens of ,kalymma1 which appear to be identical in essential features with ,unger's type-species1 are from ,kentucky1 some from the ,genessee shales of ,upper ,devonian age and others from beds 7,waverley shales7 believed to be ,lower ,carboniferous4 ,through the kindness of ,prof4 ,bower ,i have had an opportunity of examining sections from the older horizon in his possession4 ,the transverse section reproduced in fig4 #def has a diameter of #ch #bb cm4#dig3 on one side the radially placed plates of stereome are clearly shown1 and in the outer portion of the ground-tissue is a ring of vascular bundles varying in size and shape but with a general tendency to a radially elongated form4 ,the ground-tissue consists of homogeneous parenchyma3 in one place ,i noticed what appeared to be a large secretory canal1 but secretory tissue1 generally at least1 is unrepresented4 ,the xylem is composed of imperfectly preserved elements1 which appear to have scalariform pits2 spiral protoxylem strands1 embedded in the metaxylem as two or four groups1 occur near the ends of the long axis of the bundle and in some cases also near the centre4 ,the phloem probably surrounded the xylem1 though it is not certain whether the arrangement was collateral or concentric3 there are no secondary-xylem tracheids1 though in some places ,i noticed a tendency to a radial disposition of cells at the periphery of the vascular tissue simulating an early stage of secondary growth4 ,unger's second species ,kalymma striata is characterised by an arrangement of the bundles similar to that in a petiole described by ,scott and ,jeffrey as ,calamopteris ,hippocrepis which differs from ,kalymma in the partial substitution of bands of vascular tissue for separate bundles and to some extent in the disposition of the bundles4 ,the two types of petiole ,kalymma and ,calamopteris1 as ,scott and ,jeffrey state1 are very closely allied4 ,dawson and ,penhallow#dih have also described ,kalymma grandis from ,kentucky but they1 like ,unger1 mistook the hypodermal stereome for an outer zone of vascular bundles4 ,the petioles from ,germany and ,north ,america included under the name ,kalymma grandis1 though too similar to be referred to different species1 no doubt represent petioles of stems which are unquestionably distinct types3 as in the case of ,myeloxylon in its relation to the genus ,medullosa1 ,kalymma stands for several closely allied forms of petioles belonging to several species of ,calamopitys4 ,illustration3 ,fig4 #def4 ,kalymma grandis4 7,from a section in the possession of ,prof4 ,bower2 #d47 ,eristophyton4 ,zalessky4 ,eristophyton fasciculare 7,scott74 ,the generic name ,eristophyton#dii was proposed by ,zalessky#ejj for two incomplete stems of ,lower ,carboniferous age provisionally#eja referred by ,scott to ,araucarioxylon and subsequently to ,calamopitys#ejb4 ,the species ,e4 fasciculare was founded on material obtained by ,dr ,kidston from the ,lower ,carboniferous of ,dumbarton1 ,scotland1 and on a specimen in the ,williamson collection from ,northumberland4 ,there is a small pith of parenchyma1 #b-c mm4 in diameter1 with eight strands of primary xylem of varying diameter 7fig4 #deg7 and in each a single protoxylem-group4 ,the primary xylem elements are considerably larger than the secondary tracheids4 ,these xylem-bundles are leaf-traces and their disposition points to a phyllotaxis of 4 ,the traces attain their maximum size when about to pass out through the secondary xylem4 ,the tracheids are reticulate and scalariform while some have an intermediate type of pitting4 ,a leaf-trace on reaching the pith gradually moves further from the xylem-cylinder and may be separated from it by #b-f layers of parenchyma3 as it passes down the pith the protoxylem strand assumes an almost endarch position consequent on the reduction of the centripetal xylem4 ,in ,scott's words1 #8each circummedullary strand branches at regular intervals2 the one branch1 that on the anodic side turned towards the course of the genetic spiral1 becomes the leaf-trace and passes out1 while the other continues its course up the stem as a reparatory strand1 until the next leaf of the orthostichy has to be supplied#ejc4' ,the secondary xylem consists almost entirely of tracheids with #c-d rows of pits on the radial walls and medullary rays usually one cell broad varying in depth from #a or #b to #af or more cells4 ,a characteristic feature of the secondary xylem is the occurrence on its inner face of numerous short and broad tracheae similar to the still larger tracheae in the primary stele of ,megaloxylon#ejd4 ,nothing is known as to the behaviour of the leaf-trace in the extrastelar region1 but the fact that an outgoing trace was found to have two protoxylems points to a subdivision similar to that of the foliar bundles of ,calamopitys ,saturni4 ,a well-marked difference between ,eristophyton fasciculare and ,calamopitys and ,lyginopteris is the more compact structure of the secondary wood2 it is pycnoxylic and not manoxylic4 ,prof4 ,zalessky in criticising the use of the generic title ,calamopitys puts forward several arguments in support of his institution of a new designation3 7i7 the primary xylem strands of ,eristophyton are not confined to the periphery of the pith as is the case in ,calamopitys ,saturni1 though he speaks of one leaf-trace in the latter species separated by several layers of cells from the xylem-cylinder2 7ii7 some of the pith-cells have thick walls and dark contents in distinction to the homogeneous parenchyma of ,calamopitys1 a feature of little importance2 7iii7 the difference in the structure of the secondary wood already alluded to1 though this loses some of its significance by the occurrence of narrower rays1 more like those of ,eristophyton1 in ,c4 annularis2 7iv7 the more elliptical and broader pits in the secondary tracheids in place of the more regular hexagonal form in ,calamopitys4 ,while admitting a certain degree of relationship between the two types1 ,zalessky asserts that as yet we have insufficient evidence to justify their generic union4 ,scott#eje maintains that ,zalessky does not attach sufficient weight to the form and mesarch structure of the primary xylem bundles as a feature common to both genera4 ,illustration3 ,fig4 #deg4 ,eristophyton fasciculare4 ,transverse section showing the relation of primary 7black7 to secondary xylem4 7,after ,scott47 ,eristophyton ,beinertianum 7,goeppert74 #ahej4 ,araucarites ,beinertianus ,goeppert1 ,mon4 ,foss4 ,conif4 p4 #bcc1 ,pls4 #db1 #dc4 #ahgb4 ,araucarioxylon ,beinertianum ,kraus1 in ,schimper's ,trait4 ,pal4 ,vol4 ii4 p4 #cha4 #ahhh4 ,araucarites ,beinertianus ,goeppert and ,stenzel1 ,abh4 ,k4 ,preuss4 ,akad4 ,wiss4 p4 #cj1 ,pl4 iv4 #aijb4 ,calamopitys ,beinertiana ,scott1 ,trans4 ,r4 ,soc4 ,edinb4 ,vol4 #dj1 p4 #cda1 ,pls4 i41 iv41 v4 #aijiejf4 ,ullmannites ,beinertianus ,tuzson1 ,result4 ,wiss4 ,erforsch4 ,balatonsees1 ,bd i4 ,teil i4 p4 #bd4 #aiaa4 ,eristophyton ,beinertianum ,zalessky1 ,com4 ,geol4 ,st ,ptersb4 p4 #bd4 ,the pith1 #ac-ae mm4 in diameter1 is rather larger than in ,e4 fasciculare and is characterised by the occurrence of dark sclerotic nests surrounded by radially disposed rows of parenchyma4 ,the primary xylem strands are more numerous and smaller than in ,e4 fasciculare and these increase in diameter as they approach the secondary wood4 ,in places the primary xylem elements form a more or less continuous band as in ,calamopitys annularis4 ,the largest leaf-trace bundles at the periphery of the pith are mesarch 7fig4 #deh71 but as each trace passes down the pith the reduction in the centripetal xylem is carried further than in ,e4 fasciculare until the xylem-strand becomes endarch in the lower part of its course4 ,the secondary tracheids have usually two contiguous rows of pits and the medullary rays are one cell broad4 ,illustration3 ,fig4 #deh4 ,eristophyton ,beinertianum4 ,a strand of primary xylem1 showing the protoxylem1 px1 abutting on the secondary xylem4 7 #ce4 ,after ,zalessky47 ,there can be no doubt as to the generic identity of the two species referred to ,eristophyton1 but the question as to the degree of affinity to ,calamopitys is more difficult to settle4 ,there is force in ,zalessky's contention that these two stems should not be retained in ,calamopitys3 the recently described ,american species1 ,c4 americana ,scott and ,jeffrey1 gives emphasis to the view that the restriction of ,calamopitys to the ,german 7and ,american7 types is the safer course4 ,while ,calamopitys as thus restricted is almost certainly a ,pteridosperm1 the inclusion of the types referred to ,eristophyton in the same category rests on a more slender basis4 ,,cladoxyleae4 ,this order was founded by ,unger#ejg for some imperfectly preserved stems from ,palaeozoic strata in ,thuringia and in it he included the two genera ,cladoxylon and ,schizoxylon4 ,there is some doubt as to the precise age of the ,thuringian beds2 they were assigned by ,richter to the ,devonian system and subsequently placed in the ,culm3 ,solms-,laubach in his later reference to ,unger's plants favours a ,devonian horizon#ejh4 ,unger included the ,cladoxyleae in the ,lycopodiales1 and though this conclusion is not accepted the position of the order is still uncertain4 ,his genus ,schizoxylon has no claim to generic separation from ,cladoxylon4 ,an inspection of the illustrations in the memoir by ,richter and ,unger reveals a striking resemblance in the main anatomical features between several types assigned to different genera and distributed among the ,cladoxyleae and ,rhachiopterideae 7a term first used by ,corda for petrified rachises or petioles of ferns7 and other orders4 ,solms-,laubach#eji1 to whom our more accurate information as to ,unger's plants is chiefly due1 is inclined to regard the specimens referred by ,unger to the genus ,arctopodium as young stems of ,cladoxylon1 and he draws attention to a close similarity between ,hierogramma1 another of ,unger's genera1 and ,cladoxylon4 ,paul ,bertrand#eaj goes further in considering that the following genera represent one generic type1 namely ,syncardia 7fig4 #dei1 ,f71 ,hierogramma1 ,arctopodium1 ,cladoxylon1 and ,schizoxylon4 ,the same author interprets the fossils so named by ,unger as stems and does not agree with the inclusion of any of them in the ,rhachiopterideae4 ,without losing sight of the fact that ,bertrand's conclusion is not based on proof but is the expression of a view suggested by a close agreement in general anatomical plan1 ,i venture to adopt the designation ,cladoxylon in a wide sense primarily on the ground that ,bertrand's view is probably correct and in part for the sake of convenience of description4 ,as ,unger's species of ,cladoxylon differ from one another in features which may fairly be regarded as of minor importance1 they are included under one specific name4 ,cladoxylon4 ,unger4 ,cladoxylon mirabile ,unger#eaa4 ,the following are regarded as specifically identical with or closely allied to ,cladoxylon mirabile3 ,c4 dubium1 ,schizoxylon taeniatum1 ,hierogramma mysticum1 ,syncardia pusilla1 ,arctopodium insigne and ,a4 radiatum#eab4 i4 ,stems4 ,the stems assigned to ,cladoxylon are characterised by a complex system of steles1 either simple or branched and occasionally anastomosing1 presenting in transverse section the form of oval or cylindrical strands or narrow1 straight or curved bands arranged on a more or less clearly marked radial plan 7fig4 #dei1 ,a1 ,b1 ,d74 ,in some stems the primary vascular tissue is enclosed by secondary xylem and phloem 7fig4 #dfj1 ,b71 while in others 7,unger's ,arctopodium1 ,hierogramma#eac1 ,syncardia7 there is no evidence of secondary thickening4 ,the diagrammatic drawing represented in fig4 #dei1 ,f1 shows a section of a small axis1 regarded by ,unger and ,solms as a petiole 7#c mm4 in diameter71 containing four vascular strands composed exclusively of primary xylem1 each with one or1 in the case of a double strand1 two protoxylem groups4 ,this type may be a slender stem or branch or possibly a petiole4 ,the other extreme1 as regards complexity of vascular structure1 is represented by such stems as those shown in fig4 #dei1 ,a1 ,b1 ,d4 ,in ,unger's ,cladoxylon mirabile 7fig4 #dei1 ,a2 fig4 #dfj1 ,b7 the stem reaches a diameter of #c cm4 and consists of several radially disposed plates of vascular tissue with an occasional smaller oval or cylindrical stele embedded in a ground-tissue composed of thick-walled cells4 ,the plates are curved like a ,,uu or sinuous and not infrequently anastomosing4 ,in a section of this type figured by ,unger the vascular plates appear to form a complex anastomosing system1 but ,solms#ead states that the drawing exaggerates the amount of fusion between the strands1 and an examination of a section in the collection of the ,english ,geological ,survey cut from ,unger's specimen enables me to confirm this statement4 ,each vascular plate consists of a narrow median region composed of primary tracheids with a scalariform type of pitting surrounded by secondary tracheids with interspersed medullary rays one cell broad4 ,the thickness of the secondary xylem varies considerably in the same specimen and in places this tissue is hardly represented1 a fact of importance in view of the very striking resemblance between ,arctopodium and ,cladoxylon1 the sections referred by ,unger to the former genus having steles without any secondary xylem4 ,the occurrence of one or two elongated spaces 7shown in black in fig4 #dei1 ,a7 near the distal end of each plate mark the position of the protoxylem tracheids4 ,fig4 #dei1 ,c1 represents a stele of a stem referred by ,unger and by ,solms to ,cladoxylon dubium which shows the typical ,cladoxylon structure1 namely the central primary xylem with distally placed protoxylem and the enclosing sheath of secondary xylem4 ,in the stem shown in fig4 #dei1 ,d 7,c4 dubium7 there are #ab steles1 each constructed on the plan already described1 differing in their relatively broader and shorter form and in the greater breadth of the secondary xylem from those seen in fig4 #dei1 ,a 7,c4 mirabile74 ,the black areas in fig4 #dei1 ,a1 show the primary xylem1 and the protoxylem is seen in fig4 #dei1 ,c4 ,a stem described by ,dawson#eae as ,asteropteris noveboracensis from ,devonian beds is compared by him with ,unger's ,cladoxylon mirabile and regarded as possibly allied to it4 ,the radial plates of xylem in ,dawson's plant meet in the centre like those of ,asterochlaena and the leaf-traces are of the ,clepsydropsoid type4 ,illustration3 ,fig4 #dei4 ,a1 ,cladoxylon mirabile1 section of stem2 ,b1 ,cladoxylon taeniatum1 section of stem2 ,c1 ,cladoxylon dubium1 section of stele2 ,d1 ,c4 dubium1 section of stem2 ,e1 ,cladoxylon 787 mirabile1 section of petiole2 ,f1 ,syncardia pusilla2 ,g1 development of leaf-trace in ,cladoxylon taeniatum4 7,a-,e1 after ,solms-,laubach2 ,f1 after ,unger2 ,g4 after ,p4 ,bertrand47 ,the type of stem for which ,unger founded his genus ,schizoxylon is represented in fig4 #dei1 ,b2 there are five small steles in the centre and external to these eleven radially arranged plates1 with oval steles between them1 in the peripheral region of the stem4 ,each stele consists of primary 7black in the figure7 and secondary xylem and agrees with the steles in the other stems4 ,from the type of stem illustrated by ,cladoxylon mirabile to that on which the genera ,arctopodium#eaf and ,hierogramma#eag were founded is a very small step3 the vascular tissue has the same characters both as regards gross and minute anatomy1 but there is no evidence of cambial activity in the stems referred to the two latter genera1 a difference in itself hardly worthy of generic recognition4 ii4 ,leaves4 ,before describing a second type of stem referred to ,cladoxylon it is important to consider briefly such evidence as we have as to the vascular supply of the leaves4 ,nothing is known of the reproductive organs and there is no satisfactory information with regard to the form of the fronds4 ,solms-,laubach has described the only known example of a lateral branch of a ,cladoxylon stem 7fig4 #dei1 ,e73 this has a single concentric vascular strand of plate-like form with two blunt projections and there are four protoxylem-groups1 two in the angle of the plate and two at the base of the projections4 ,the structure is essentially fern-like2 the xylem is wholly primary4 ,this type of vascular strand agrees fairly closely with that of a petiole described by ,unger as ,megalorhachis elliptica1 a section of which is in the ,museum of the ,geological ,survey#eah4 ,the petiole is oval in section and laterally winged1 and the meristele is tangentially elongated and has two blunt projections almost identical with those in fig4 #dei1 ,f4 ,there is no evidence as to the nature of the supporting stem1 but there can be little doubt as to the close connexion with ,megalorhachis and the section shown in fig4 #dei1 ,f4 ,in a note published in #aijh ,p4 ,bertrand stated that he had identified several of ,unger's genera as stems which bore leaf-traces having the form and structure of ,clepsydropsis1 one of the types referred by ,unger to the ,rhachiopterideae and described in the second volume of this work#eai as a ,coenopteridean petiole4 ,bertrand points out that in the oval or plate-like steles of ,cladoxylon1 ,arctopodium1 ,hierogramma1 etc41 there is a single protoxylem group near the distal end of the primary xylem1 and he adds that the leaf-traces were formed of strands cut off from the distal portions of the vascular plates4 ,similarly the hour-glass-like leaf-trace in the primary rachis of ,clepsydropsis gives off from each end a ring of xylem to supply a secondary rachis4 ,these laterally detached annular strands are1 he believes1 similar to the leaf-trace cut off from the steles in a ,cladoxylon stem4 ,the conclusion is that ,cladoxylon is a fern stem and its leaf-trace represents the simplest form of the ,clepsydropsis type1 namely an oval bundle of xylem with a central protoxylem1 which is also the form of the trace given off from the stem of ,asterochlaena4 ,solms#ebj1 while admitting that ,bertrand may be correct in uniting under one genus ,cladoxylon and such types as ,syncardia1 ,hierogramma1 and ,arctopodium1 disagrees with the view that they are ,clepsydropsis stems4 ,a ,clepsydropsoid leaf-trace has never been found in direct association with any of the stems of the ,cladoxylon type and such evidence as there is indicates a leaf-trace of an entirely different form 7fig4 #dei1 ,e74 ,in his more recent memoir on ,asterochlaena ,bertrand#eba draws attention to ,solms' figures of a stele of ,cladoxylon 7fig4 #dei1 ,c7 in which the distal portion is on the point of being separated as a small annular strand4 ,this1 ,bertrand considers1 would gradually become converted into a ,clepsydropsis form of stele as it passed to the petiole4 ,bertrand's drawings made from a section of ,cladoxylon taeniatum 7,ung47 7fig4 #dei1 ,g7 illustrate successive stages in the departure of a leaf-trace from one of the plate-like steles of the stem 7fig4 #dei1 ,b74 ,in fig4 #dei1 ,g1 #a1 a piece of the stele is detached and near its extremity is a group of thin-walled cells with protoxylem3 a later stage is seen in fig4 #b1 and in fig4 #c a small ring of xylem is being detached which1 ,bertrand assumes1 would later in its course be converted into the ,clepsydropsoid strand 7fig4 #d71 which consists of primary tissue4 ,the weak point in ,bertrand's contention#ebb is the absence of any proof of a true ,clepsydropsoid trace in connexion with a ,cladoxylon stem1 and there is a strong probability that the leaf-trace of ,cladoxylon has the form shown in fig4 #dei1 ,e4 ,cladoxylon ,kidstoni ,solms-,laubach#ebc4 ,this species1 founded on imperfectly preserved material in ,dr ,kidston's collection from ,lower ,carboniferous rocks in ,berwickshire1 is referred to ,cladoxylon on evidence that cannot be regarded as convincing4 ,the type-specimen consists of a small piece of stem about #c cm4 in breadth showing three complete oval steles and portions of two others which seem to be in their original position and probably formed part of a series of peripheral steles such as those shown in fig4 #dei1 ,d4 ,each stele consists mainly of secondary xylem 7fig4 #dfj1 ,a7 with some crushed tissue1 presumably phloem1 on its outer face4 ,the secondary xylem is narrower on the inner side of each stele where a wedge-shaped piece is partially detached4 ,in the centre there is a narrow area parallel to the long axis of the stele containing crushed tissue which probably consists of parenchyma and primary xylem1 but the preservation is very imperfect4 ,the secondary xylem has a fairly compact structure and the rays are narrow1 #a-aj cells in depth4 ,the pits of the tracheids are described by ,solms as scalariform with occasionally two rows of elliptical pits on the radial walls4 ,a careful examination of the type-specimen leads me to describe the pits as uniseriate and transversely elongated1 very like those of ,protopitys1 or biseriate and almost circular like those of ,conifers1 the pits of the two rows being alternate or sometimes opposite 7fig4 #dfj1 ,c73 in places three rows of bordered pits are present4 ,there is a certain degree of resemblance between the steles of this species and those of the ,south ,african stem ,rhexoxylon#ebd1 but the data are inadequate for a satisfactory comparison4 ,illustration3 ,fig4 #dfj4 ,a1 ,c4 ,a single stele and tracheids of ,cladoxylon ,kidstoni4 7,kidston ,coll4 #fcj ,b1 #fcj ,c47 ,b4 ,cladoxylon mirabile1 part of a stele4 7,museum of ,practical ,geology1 #aehgb47 ,there is a close similarity between the vascular systems of ,cladoxylon and ,medullosa1 but an obvious difference is the substitution of the oval1 transversely elongated1 pits on the xylem elements for the multiseriate pitting of ,medullosa4 ,in ,cladoxylon ,kidstoni the pitting shows transitional forms between a narrow scalariform uniseriate type and a biseriate or triseriate arrangement similar to that in the ,araucarineae and ,cordaitales4 ,in ,cladoxylon1 as limited by ,unger1 the presence of secondary wood is a generic feature1 but by the inclusion of ,arctopodium and other forms this character no longer holds good4 ,the inclusion of these more fern-like stems without secondary xylem brings ,cladoxylon 7in the wider sense7 into closer contact with ,asterochlaena1 a comparison previously suggested by more than one author4 ,in ,medullosa the development of secondary xylem is on a larger scale than in ,cladoxylon1 and the vascular system of the former genus assumes a more complex form4 ,moreover the ,myeloxylon type of petiole1 which is a distinctive feature of ,medullosa1 differs widely from any form of leaf-trace associated with ,cladoxylon4 ,vlkelia4 ,solms-,laubach4 ,vlkelia refracta 7,goeppert74 ,the generic name ,vlkelia#ebe was proposed by ,solms-,laubach#ebf as a substitute for ,sphenopteris#ebg in the case of some petrified stems or petioles associated with fragmentary impressions of fronds from ,lower ,carboniferous rocks in ,silesia4 ,both leaf-impressions and petrifactions were included in the genus ,sphenopteris3 ,solms1 while retaining ,goeppert's designation for the leaf fragments1 proposed a new generic name for the petrifactions on the ground that there is insufficient evidence of their connexion with the leaves4 ,the short account of ,goeppert's petrified specimen given by ,graf ,solms-,laubach in his #8,fossil ,botany#ebh' is supplemented by a fuller description in a later paper4 ,the fragments of highly compound fronds are characterised by very small filiform ultimate segments1 but the specimens are too imperfect to afford a clear idea of the habit of the leaf4 ,the #8stem' bears a close superficial resemblance to that described by ,unger as ,cladoxylon dubium 7fig4 #dei1 ,c1 ,d7 and was regarded by him as an example of that species3 it contains several radially placed steles represented by fairly well-preserved xylem1 but no phloem has been recognised4 ,the steles vary in size and shape3 five reach almost to the centre 7fig4 #dfa1 ,a7 and smaller xylem groups occupy a peripheral position4 ,each stele is excentric in structure and consists of 7i7 an outer zone of secondary tracheids of horse-shoe form in transverse section1 but the apparent gap in the secondary xylem on the outer edge of each stele is due to the crushing of the tracheal tissue and to its smaller breadth in the distal part of each group2 this is shown in fig4 #dfa1 ,b1 where the apparent gap is seen to be occupied by distorted and crushed tracheids1 a1 identical with those which form the rest of the outer zone 7fig4 #dfa1 ,b1 b72 7ii7 a zone of tracheal tissue continuous with and originally identical in appearance--except that the elements are rather narrower--with the outer secondary xylem2 7iii7 an excentrically situated island composed of tracheids enclosing a small central area occupied by thin-walled parenchyma4 ,this third region1 represented by black patches in fig4 #dfa1 ,a1 in all probability represents the primary part of each stele to which the rest of the tissue has been added by the cambium4 ,a striking feature of the secondary xylem is the absence of medullary rays3 the tracheids resemble those of ,cladoxylon and ,protopitys in the transverse elongation of the pits 7fig4 #dfa1 ,d7 which form either a single row or several irregularly distributed rows4 ,the primary xylem consists in the peripheral region of tracheids with very narrow scalariform pitting which at first sight suggest close spiral bands 7fig4 #dfa1 ,c71 while the inner tracheids are either annular or reticulate and associated with elongated parenchyma4 ,the imperfectly preserved ground-tissue appears to consist of homogeneous parenchyma with radially disposed bands of stereome in the outer cortex4 ,illustration3 ,fig4 #dfa4 ,vlkelia refracta4 ,a4 ,transverse section of a specimen in the ,breslau ,museum4 ,b4 ,portion of a stele2 a1 the crushed xylem on the outer side2 b1 the inner side4 ,c4 ,longitudinal section showing the median protoxylem4 ,d4 ,tracheid from the secondary xylem4 7,after ,solms-,laubach47 ,our knowledge of ,vlkelia1 though far from complete1 justifies its generic separation from ,cladoxylon from which it differs in the lack of medullary rays and in the structure of the primary portion of each stele4 ,in the form and arrangement of the pits in the secondary tracheids ,vlkelia differs from ,medullosa and resembles ,cladoxylon4 ,the opinion expressed by ,p4 ,bertrand#ebi that ,vlkelia is probably the stem of one of the ,zygopterideae is based on the older accounts of the genus and not on the fuller description of #aiaj4 ,,protopityeae4 ,protopitys4 ,goeppert4 ,the only species so far described is that for which ,goeppert founded the genus in #ahej1 substituting ,protopitys#ecj for the name ,araucarites1 adopted in an earlier paper1 on the ground that the structure of the xylem denoted a distinct generic type4 ,the type-species is from the ,upper ,devonian rocks of ,falkenberg in ,silesia4 ,protopitys ,buchiana ,goeppert4 #ahde4 ,araucarites ,buchianus ,goeppert1 in ,wimmer's ,flor4 ,schlesien 7edit4 ii47 p4 #bah4 #ahdg4 ,pinites ,goepperti ,unger1 ,chlor4 ,protog4 p4 #ca4 #ahdg4 ,dadoxylon ,buchianum ,endlicher1 ,syn4 ,conif4 p4 #cjj4 #ahej4 ,protopitys ,buchiana ,goeppert1 ,foss4 ,conif4 p4 #bbi1 ,pl4 xxxvii4 figs4 #d-g2 ,pl4 xxxviii4 figs4 #a1 #b4 ,in his ,monograph of ,fossil ,conifers ,goeppert figured a large piece of stem consisting mainly of secondary wood and described the more important anatomical features4 ,he recognised the narrow1 transversely elongated1 pits on the radial walls of the tracheids as a feature of special interest indicating a type of pitting transitional between that of ,ferns and ,conifers4 ,a further description was given by ,kraus#eca who included under ,goeppert's name both the ,falkenberg stem and a second specimen from ,basel though the latter is ,triassic in age and a distinct plant2 he suggested a comparison of ,protopitys with ,sigillaria and ,stigmaria rather than with ,conifers4 ,it is1 however1 to ,graf ,solms-,laubach#ecb that we owe the most thorough account of this species4 ,nothing is known of the leaves or reproductive organs4 ,the largest piece of stem is nearly #a ft in diameter and consists mainly of secondary xylem resembling that of ,conifers and ,cordaites except in the form of the bordered pits on the radial walls of the tracheids 7fig4 #dfb1 ,d74 ,the centre of the stem is occupied by a parenchymatous pith1 elliptical in transverse section1 enclosed by a band of primary xylem composed of large polygonal tracheids 7fig4 #dfb1 ,c1 x7 characterised by a delicate scalariform pitting on all their walls 7fig4 #dfb1 ,e74 ,the primary xylem forms a narrow layer on the sides of the ellipse1 #a-c elements broad 7fig4 #dfb1 ,a1 ,b71 but it increases in breadth at the ends of the long axis where the tracheids are intermixed with parenchyma4 ,the primary xylem and pith-tissue at the ends of the major axis of the central region assume different forms at different levels1 owing to the detachment of leaf-traces and the consequent formation of foliar gaps as portions of the primary xylem pass obliquely outwards into the secondary xylem on the way to the distichously arranged alternate leaves4 ,the diagram1 fig4 #dfb1 ,a1 shows the inner part of the secondary xylem 7see also fig4 #dfb1 ,c1 x7 which at one end1 lt1 has formed an oval group about to pass out as a leaf-trace3 at the opposite end the strand is detached and divided into two equal branches4 ,the two swellings of the primary xylem ellipse shown at a in figs4 #dfb1 ,a and ,b1 are a characteristic feature3 these are clearly seen after the leaf-trace has become detached2 at the inner edge of each of them there appears to be a protoxylem strand4 ,after the formation of a foliar gap these swellings of the xylem gradually meet and so re-establish continuity below the outgoing leaf-trace4 ,no protoxylem has been detected in the actual trace1 which is believed to be concentric4 ,the formation of the leaf-gap and the shoulders bordering it constitute interesting filicinean features1 recalling corresponding characters in solenostelic ,ferns4 ,at the upper end of the diagram1 fig4 #dfb1 ,b1 the outgoing leaf-trace is undergoing dichotomy while at the opposite end the trace has passed out of view4 ,the secondary xylem shows incomplete rings or arcs of narrower elements1 which at first sight give the impression of annual rings3 the occurrence of similar incomplete or pseudo-rings is a common feature in ,lepidodendron and other ,palaeozoic stems4 ,the secondary tracheids 7#edd in tangential diameter1 #fhe in radial diameter7 have usually a single series of broadly oval bordered pits on the radial walls with here and there two rows 7fig4 #dfb1 ,d74 ,in one case only were the pits of the medullary rays recognised 7fig4 #dfb1 ,f74 ,the rays are uniseriate1 generally #a-b cells deep1 but occasionally #c cells in depth and very rarely deeper4 ,the cambium is of the normal type1 and in some specimens secondary phloem was found consisting of bands1 #d-e layers broad1 of stone-cells alternating with tubular thin-walled elements1 presumably sieve-tubes4 ,illustration3 ,fig4 #dfb4 ,protopitys ,buchiana4 ,a1 ,b4 ,central region of the stem showing the pith1 the primary xylem 7black in fig4 ,a7 and 7,a7 the inner part of the secondary xylem2 a1 shoulders of xylem at the leaf-gaps2 lt leaf-trace2 px protoxylem4 ,c4 ,secondary1 x1 and primary xylem1 x4 ,d4 ,radial longitudinal section of the secondary xylem4 ,e4 ,scalariform tracheid of the primary xylem4 ,f4 ,pits on the medullary-ray cells4 7,after ,solms-,laubach47 ,as ,solms-,laubach says1 it is highly probable that each leaf-trace1 which forks close to its exit from the primary xylem1 became further subdivided before reaching the leaf4 ,morphologically1 ,protopitys is of special importance as a type possessing characters that indicate a connexion with ,conifers or ,cordaitean genera1 notably the structure of the secondary wood1 while the presence of foliar gaps is a feature reminiscent of ,ferns4 ,the primary xylem resembles that of some of the ,palaeozoic arborescent ,lycopodiales1 but in ,protopitys the interruptions in this tissue are due to the emission of leaf-bundles1 whereas in the discontinuous primary xylem of some ,sigillarias#ecc the gaps have no connexion with leaf-traces4 ,moreover the distichous leaves of ,protopitys and the larger1 branched1 leaf-traces are other distinguishing features4 ,the pitting of the primary xylem is like that in the ,lycopodiales and ,filicales1 while that of the secondary wood shows a closer approach to the coniferous type4 ,a comparison may also be made with the transversely elongated pits of ,cladoxylon ,kidstoni#ecd4 ,a piece of wood agreeing anatomically with the ,silesian species of ,protopitys has been found in the ,yoredale rocks of ,england#ece4 ,the peculiarities of the genus have been emphasised by ,solms-,laubach by the institution of a family-name ,protopityeae3 the genus is essentially a generalised type exhibiting in the structure of its stem both ,filicean and ,coniferous features4 ,the bordered pits differ from those in recent ,conifers in their flatter form1 but in this respect they exhibit a closer agreement with the transversely stretched pits of ,xenoxylon phyllocladoides ,goth4#ecf1 a ,mesozoic species4 ,,chapter ,,xxxiii4 ,,cordaitales4 ,a4 ,,poroxyleae4 ,poroxylon4 ,renault4 ,in #ahgi ,renault#ecg briefly summarised the anatomical features of some silicified vegetative shoots from the ,permian of ,autun for which he instituted a new family1 the ,poroxyleae4 ,the more complete account contains a description of two species1 ,poroxylon ,boysseti and ,p4 ,duchartrei3 the latter was afterwards recognised as a stem of ,heterangium4 ,renault considered this new genus to be closely allied to ,sigillaria and ,sigillariopsis and pointed out its resemblance to ,cordaites4 ,additional species have since been described but as yet the genus has not been found outside ,france in ,permo-,carboniferous strata of ,autun and the ,st tienne district4 ,the results of a more detailed investigation of the anatomy of the genus were published by ,bertrand and ,renault in #ahhb and since then#ech ,bertrand1 ,renault1 and ,scott have added to our knowledge of this interesting type4 ,in several respects ,poroxylon stems present a striking resemblance to ,lyginopteris1 but the recent discovery of the genus ,mesoxylon has given greater significance to the characters in which ,poroxylon agrees with representatives of the ,cordaitales4 ,our knowledge of the genus1 though exceptionally full with regard to the anatomy of vegetative shoots1 does not include any precise information as to the reproductive organs4 ,the slender cylindrical stems1 not exceeding #b-c cm4 in diameter in specimens so far recorded1 bore large broadly linear leaves similar in form and venation to those of some species of ,cordaites which were attached singly to slightly swollen nodes separated from one another by internodes several centimetres long4 ,the base of the rather fleshy lamina passes imperceptibly from the narrow lower portion into a tangentially expanded petiole which forms a decurrent ridge on the stem4 ,axillary buds frequently occur4 ,little is known of the leaf-impressions1 but if ,grand',eury#eci is correct in his identification of certain specimens from ,french ,stephanian beds as the leaves of ,poroxylon1 the lamina reached a length of #a met4 and a breadth of #ae-bj cm4 ,in habit the stems probably resembled some of the larger-leaved ,bamboos4 ,the only evidence bearing on the nature of the reproductive organs is furnished by ,grand',eury who believes that some ,rhabdocarpus seeds and bractless inflorescences associated with the leaves assigned to ,poroxylon belong to that genus4 ,the single cylindrical stele has a relatively large solid pith1 the perimedullary region being characterised by the occurrence of a row of primary crescentic strands of centripetal xylem of exarch type1 though not improbably in some cases slightly mesarch1 varying in size and shape and forming single or paired bundles4 ,these strands represent the xylem of collateral leaf-traces similar to those of ,lyginopteris but differing in the absence of well-defined centrifugal elements3 the curved form of some of the xylem strands gives them an appearance similar to that of the leaf-traces of ,lyginopteris4 ,the leaf-traces1 except in the lower part of their course through the pith1 are double and pass through several internodes before the centripetal tracheids die out4 ,the secondary xylem 7fig4 #dfc7 is manoxylic and very similar to that of ,lyginopteris though rather less parenchymatous4 ,the secondary phloem and cambium are often very well preserved4 ,no endodermis and no distinct pericycle has been recognised4 ,the cortex is parenchymatous and1 like the pith and to some extent the phloem1 contains numerous secretory sacs2 in the outer cortex the presence of hypodermal strands is a prominent feature4 ,at an early stage in the growth of the stem a deep-seated phellogen forms secondary tissue both externally and internally and decortication ensues4 ,illustration3 ,fig4 #dfc4 ,poroxylon ,edwardsii4 ,a4 ,transverse section of stem4 ,b4 ,the central region of another stem of the same species4 7,a1 #i2 ,university ,college ,collection2 ,b1 from a photograph supplied by ,prof4 ,bertrand of a specimen in the ,renault ,collection1 ,paris47 ,the bundle of each leaf-trace is accompanied by an arc of secondary centrifugal xylem as it passes through the secondary wood and this is retained in the leaf except in the finer veins4 ,after entering the petiole the leaf-trace branches and an arc of bundles is produced1 the concave side facing the upper surface of the thick lamina 7fig4 #dfd1 ,a74 ,further reference is made to the structure of the leaves in the description of ,poroxylon stephanense4 ,the specimens of roots so far described are characterised by a diarch plate of primary xylem and two masses of secondary vascular tissue separated by two medullary rays opposite the protoxylems4 ,bertrand mentions the occurrence of roots of ,p4 stephanense with more than two protoxylem strands4 ,the phellogen was produced in the pericycle as in the roots of recent ,gymnosperms4 ,it is suggested by ,lignier#edj that some silicified rootlets from ,grand' ,croix 7,loire7 described by him as ,radiculites reticulatus and at first compared with roots of ,sequoia may belong to some ,cordaitalean plant1 possibly ,poroxylon4 ,poroxylon ,edwardsii ,renault4 ,this species#eda affords a good illustration of the generic characters already summarised4 ,the strap-like leaves are fleshy and the occasionally forked1 parallel or slightly divergent1 veins are embedded in a homogeneous mesophyll with hypodermal strands of mechanical tissue4 ,the pith consists of parenchyma in vertical series with scattered secretory sacs and differs from that of ,cordaites and ,mesoxylon in the absence of transverse discs4 ,there are #ac primary-xylem strands close to the inner edge of the secondary wood3 the centripetal tracheids are scalariform or have multiseriate pitting like that in the secondary xylem4 ,the structure of the leaf-traces is clearly shown in fig4 #dfd3 the double trace seen in fig4 #dfd1 ,c1 has two protoxylem-strands accompanied by some parenchyma1 and these are almost enveloped by the metaxylem tracheids which abut on the secondary wood4 ,at this stage in its course1 that is just before bending outwards1 the centripetal xylem reaches its maximum development and the trace forms a prominent and broad twin-strand in striking contrast to the two narrower and tangentially extended strands shown in fig4 #dfd1 ,e1 ,d4 ,each of these strands with a single protoxylem-group would at a higher level assume the broader and more compact form and contain two protoxylems as in fig4 #dfd1 ,c4 ,the tracheids of the secondary xylem have #d-g alternate rows of contiguous alternate pits on the radial walls3 the medullary rays are #b-c cells broad and may be #fj cells deep4 ,according to ,renault#edb several small oblique pits occur on the radial walls of the ray cells4 ,the secondary phloem1 separated by a normal cambium from the xylem1 forms a broad band of sieve-tubes with lateral sieve-plates like those in ,medullosa anglica alternating with tangential rows of parenchyma4 ,the cortex is relatively narrow and in older stems is chiefly occupied by secondary tissue formed from deep-seated phellogens4 ,illustration3 ,fig4 #dfd4 ,poroxylon4 ,a1 ,b1 ,poroxylon ,boysseti4 ,a1 transverse section of leaf in the region of lateral expansion of the petiole2 ,b1 portion of vascular tissue of ,a4 ,c-,e1 ,poroxylon ,edwardsii4 ,c1 leaf-trace showing recent separation of the two protoxylems2 ,d1 leaf-trace at a lower level with more widely separated protoxylems1 px2 ,e1 leaf-trace intermediate between ,c and ,d4 7,from photographs supplied by ,prof4 ,bertrand47 ,poroxylon ,boysseti ,renault4 ,the stems of this species agree closely with those of ,p4 ,edwardsii1 the chief difference being in the structure of the secondary phloem which does not show the regular concentric alternation of sieve-tubes and parenchyma4 ,poroxylon stephanense ,bertrand and ,renault4 ,this the oldest species1 from ,stephanian beds at ,grand' ,croix1 differs in no essential features from the other representatives of the genus4 ,it is from a study of the leaves of this type that ,bertrand and ,renault have obtained most of the facts with regard to the anatomy of ,poroxylon foliage4 ,in the median region of the fleshy leaf the bundles are characterised by a comparatively large amount of centripetal xylem accompanied by a considerable development of secondary centrifugal tracheids3 the bundles are connected laterally by both centripetal and centrifugal xylem and thus at certain levels in the lamina the vascular tissue has the form of a continuous plate 7fig4 #dfd1 ,a1 ,b74 ,the veins become independent on branching and near the edge of the lamina they consist only of primary elements4 ,secretory sacs of elongated form are scattered in the homogeneous mesophyll1 and thick stereome-strands underlie the epidermis4 ,the epidermal cells are rectangular and rows of stomata occur on both surfaces4 ,b4 ,,cordaiteae4 ,cordaites4 ,unger4 ,a preliminary statement with regard to nomenclature may serve to remove possible misconceptions in connexion with the application of the generic name ,cordaites4 ,it has been the general practice to apply this name to certain forms of linear leaves which are particularly abundant in ,carboniferous and ,permian strata in ,europe and ,north ,america1 and in recent years a few palaeobotanists have substituted ,cordaites for ,noeggerathiopsis as the more suitable designation for ,permo-,carboniferous specimens abundant in the rocks of ,gondwana ,land4 ,it has been customary to assign to ,cordaites certain reproductive shoots1 seeds1 and stems described under the generic names ,cordaianthus1 ,cordaicarpus1 ,cordaicladus1 ,cordaioxylon1 etc4 ,stems agreeing anatomically in their main features with those of recent ,araucarineae have long been attributed to ,cordaites1 but a few years ago a new type of stem was discovered which1 though almost identical with that of ,cordaites1 is distinguished by the character of the primary xylem4 ,for this new type the name ,mesoxylon#edc was proposed4 ,nothing is known as to the reproductive organs borne on ,mesoxylon stems1 but the leaves are externally at least indistinguishable from those referred to ,cordaites4 ,it is therefore obvious that when we apply the name ,cordaites to leaves or other plant-organs1 under that designation are undoubtedly included specimens belonging both to ,mesoxylon stems and to stems with the characters of ,cordaites 7,cordaioxylon74 ,further research may enable us to subdivide ,cordaites into more precisely defined types distinguished by well-marked morphological characters1 but at present the only course would seem to be to restrict the term ,mesoxylon to petrified stems exhibiting the features of that genus and to retain ,cordaites as a comprehensive designation in accordance with the general account of the genus given in the following pages4 ,this widely distributed and mainly ,palaeozoic genus is especially well represented in the coalfields of ,france where in some localities it contributed largely to the formation of seams of coal#edd1 and it is chiefly from the researches of ,french ,palaeobotanists that our knowledge of its morphology is derived4 ,cordaites has shared the fate of most other abundant fossil plants in the distribution of its disjuncta membra among several genera and classes1 but on the whole the information that is now available enables us to reconstruct the complete plant with a greater degree of confidence than is usually attainable4 ,cordaites may be described as a forest-tree closely resembling in habit and probably in size the recent ,conifer ,agathis1 more especially such species as ,a4 macrophyllus1 ,a4 vitiensis and others with leaves considerably longer than those of the ,kauri ,pine 7,a4 australis7#ede4 ,the main stem reached a considerable height before giving off scattered branches bearing spirally disposed1 sessile1 and often crowded leaves#edf like the foliage of ,agathis4 ,the absence of any evidence of a two-ranked arrangement of leaves on lateral branches suggests a general tendency towards a vertical rather than a horizontal direction of growth4 ,the sessile and closely set leaves for the most part of leathery texture vary considerably in length and breadth in different types 7figs4 #dff-dgb73 in some the broadly linear lamina with its parallel veins and perfectly constructed ,i-shaped girders 7fig4 #dfe7 reached a length of nearly #ajj cm41 in shape like the blade of a straight broad-sword or the leaves of a ,yucca1 torn by the wind into strips2 in other forms the lamina is shorter and more obovate1 while in some the leafy shoots must have looked like slender stems of the smaller-leaved ,bamboos4 ,there is no proof that young vegetative branches with their spirally rolled leaves#edg were protected by bud-scales1 but some oval triangular scales 7fig4 #dfh1 ,c71 occasionally found in association with larger foliage-leaves1 may have served that purpose4 ,the branches from which leaves had recently fallen at the time of fossilisation are characterised by transversely elongated oval scars1 occasionally showing a slightly curved row of pits like the marks of leaf-traces on the scars of a ,horse ,chestnut1 sometimes terminating a feebly projecting decurrent leaf-cushion 7fig4 #dff1 ,c74 ,the leaves persisted for a comparatively long period as in ,araucaria imbricata1 and on older leafless branches the scars are transversely stretched2 the leaf-cushion loses its individuality and eventually the development of secondary cortical tissue causes the exfoliation of the superficial bark4 ,in the form and structure of the fertile shoots ,cordaites parts company with ,agathis2 the trees bore no cones in the ordinary sense1 but unisexual inflorescences--whether on one plant or on different individuals is uncertain--were produced in the axils or from a supra-axillary position as compound spikes or compact racemes4 ,both the longer female shoots and the shorter and more compact male branches are constructed on a similar plan4 ,the ovulate inflorescence may exceed #cj cm4 in length 7fig4 #dgi72 a stout axis bears two-ranked linear bracts subtending short lateral bud-like shoots with one or several sessile or stalked ovules 7fig4 #dhj7 between the sterile scales4 ,the seeds are platyspermic and agree much more closely with those of ,cycads and ,gingko than with the seeds of ,conifers4 ,the male inflorescence is on a smaller scale1 in habit not unlike the elongated male shoot of ,cephalotaxus pedunculata and some other ,conifers2 each bract subtends a small oval bud composed of imbricate scales and highly modified microsporophylls borne singly or in clusters 7figs4 #dha1 ,f2 #dhb74 ,a microsporophyll consists of a comparatively long pedicel bearing at its apex a few long microsporangia4 ,the term microsporophyll implies a morphological interpretation which is not accepted by all palaeobotanists1 some of whom prefer to regard the microsporangia as stamens or microsporophylls reduced to their simplest terms and sessile on an elongated flower-stalk4 ,the stem agrees very closely in its more important features with that of an ,araucaria or an ,agathis3 the primary xylem forms the inner surface of the thick cylinder of secondary wood1 merging gradually into it as in recent ,conifers2 there are no separate bundles of primary centripetal xylem4 ,the medullary rays are narrow3 in other words the secondary xylem is of the pycnoxylic type4 ,the pitting of the tracheids is ,araucarian and1 as in ,agathis1 the leaf-traces arise as twin-bundles4 ,the pith is larger than in the ,araucarineae and more homogeneous in structure2 it shares with the pith of ,juglans and some other recent plants an almost constant tendency to assume a discoid structure4 ,anatomically the leaves agree more closely in the structure of the vascular bundles with ,cycads than with ,conifers though there are points of contact with both of these classes4 ,the roots branch freely and their horizontally extended arms 7figs4 #dfh1 ,a2 #dgh7 suggest growth in swampy ground2 anatomically they conform to the recent ,gymnospermous type and there is good evidence that in some cases fungal mycelia lived symbiotically in the cortex of coralline rootlets4 ,sternberg#edh figured some leaves of ,cordaites from ,carboniferous rocks in ,bohemia under the generic name ,flabellaria in the belief that they belonged to a ,palm4 ,brongniart substituted a new name ,pycnophyllum#edi on the ground that ,corda had disproved the supposed relationship with ,monocotyledons4 ,the name ,cordaites was instituted by ,unger#eej1 his definition being based on leaf-form as well as on stem-anatomy4 ,it has recently been proposed to revive the forgotten designation ,pycnophyllum#eea1 but the reasons given are hardly likely to induce botanists to discard the familiar generic name which perpetuates the memory of ,corda4 ,as already pointed out1 the name ,cordaites1 even though employed in what has always been regarded a legitimate sense1 is no doubt often given to specimens of some other allied member of the ,cordaitales which can only be recognised as such in the case of more completely preserved material4 ,the naming of wood of the ,cordaitean type1 but which may equally well belong to another genus1 raises a difficult question3 if there is satisfactory evidence from collateral sources that the wood is that of a ,cordaites ,grand',eury's name ,cordaixylon#eeb or ,schenk's form ,cordaioxylon#eec may be used1 though there seems to be no adequate reason against the use of the name ,cordaites4 ,if there is no confirmatory evidence available and it is impossible to say whether the wood is that of a ,conifer or a ,cordaites1 or some other plant with the same type of secondary xylem1 ,endlicher's term ,dadoxylon#eed is most conveniently employed4 ,the confusion liable to follow from the use of the two generic names ,dadoxylon and ,araucarioxylon for wood of the same type differing only in geological age is an argument in favour of extending ,dadoxylon to all specimens having certain anatomical characters1 which cannot be certainly assigned either to the ,araucarineae or the ,cordaitales1 irrespective of geological age4 ,the term ,cordaicladus sometimes applied to branches is hardly necessary1 but the subgeneric names ,eu-,cordaites1 ,dory-,cordaites1 and ,poa-,cordaites1 instituted by ,grand',eury for different forms of leaf1 are frequently employed and serve a useful purpose as descriptive terms though the characters which they connote are of small importance and by no means always well defined or constant4 ,for inflorescences it is customary to adopt the name ,cordaianthus suggested by ,grand',eury as a substitute for ,antholithus and some other terms4 ,the same author uses ,rhizo-,cordaites for roots4 ,the nomenclature of seeds is more difficult3 in a few instances seeds occur in organic connexion with ,cordaitean shoots1 but there is no doubt that many platyspermic ,palaeozoic seeds preserved as detached fossils belong to ,cordaites or some other member of the group4 ,the difficulty is that in the present state of knowledge we cannot definitely determine in many cases whether a seed is ,cordaitean or whether it belonged to a genus of ,pteridosperms4 ,for this reason the account of several seeds that were probably borne on ,cordaites or some allied genus is given in a later chapter devoted to ,gymnospermous seeds4 ,there is no doubt that under the generic names ,cardiocarpus1 ,cordaicarpus1 and ,samaropsis are included true ,cordaitean seeds1 though it would be incorrect to say that all the seeds so named belong to members of the ,cordaitales4 ,cordaites reached its maximum development in the ,carboniferous and ,permian periods2 the genus or some closely allied types persisted into the ,triassic and ,rhaetic periods1 and there is reason to believe that the group was represented in some post-,rhaetic floras4 ,the genus is one of many remarkable examples of the high degree of specialisation attained by ,palaeozoic plants4 ,the complex mechanisms represented by ,cordaites and similar types give force to the conviction that we cannot hope to penetrate below the higher branches of the genealogical tree which had its roots in a period of the earth's history inaccessible to botanical investigation4 ,the plants of the present age are to a large extent the result of evolutionary tendencies more correctly described as the result of degeneration or simplification than as the latest phase in a series composed of a succession of types gradually growing in complexity4 ,cordaites is essentially a generalised type1 a composite product of an age characterised by an activity in the elaboration of the complex from the simple4 ,botanical records furnished by the geological series available for investigation furnish evidence of the sorting of characters among gradually diverging races and of changes in plant-organisation tending towards simplification and increased efficiency4 ,cordaites1 using the generic designation in a wide sense1 occurs in ,carboniferous and ,permian strata in ,europe1 ,north ,america1 and ,china2 it is recorded from several localities in ,russia and ,siberia for the most part from ,permian rocks1 from ,permo-,carboniferous 7,lower ,gondwana7 beds in ,india1 ,australia1 ,south ,africa1 and ,south ,america4 ,wood agreeing generally in the structure of its secondary tracheids with that of ,cordaites is represented in ,devonian rocks1 and there can be no doubt as to the existence of ,cordaitalean plants in pre-,carboniferous floras4 ,it is represented in the ,rhaetic flora of ,tonkin and has recently been discovered in strata probably of ,rhaetic age in ,mexico4 ,leaves4 ,it is important to recognise the fact that leaves included under the generic name ,cordaites were in many cases not borne on stems or branches with the anatomical characters of ,cordaites4 ,scott in his account of the genus ,mesoxylon says1 #8,i feel no doubt that most of the ,british specimens of ,cordaitean leaves really belong to ,mesoxylon1 which is a much commoner type of stem in the ,coal ,measure petrifications than that of ,cordaites itself#eee4' ,some of the ,cordaitean leaves were probably attached to stems of the ,poroxylon type#eef and it is not improbable that1 as investigations are extended1 additional genera of vegetative shoots will be discovered provided with leaves similar at least in external characters to those which it is customary to refer to ,cordaites4 ,in the present state of our knowledge we cannot make use of anatomical characters as criteria by which to distribute the foliage of the ,cordaites form among the genera ,cordaites1 ,mesoxylon1 and ,poroxylon1 using these names as designations of certain types of anatomical structure4 ,the specimen reproduced in fig4 #dfe is in all probability a piece of a leaf of ,cordaites principalis1 but on anatomical grounds ,miss ,benson#eeg has made it the type of a new species1 ,c4 ,felicis1 and more recently ,scott#eeh has brought forward evidence supporting the view that it is a leaf of ,mesoxylon4 ,as1 therefore1 neither impressions nor petrifications of ,cordaitean leaves can in the great majority of cases be referred with confidence to their respective genera of stems1 pending fuller information the only course would seem to be to use the name ,cordaites in a comprehensive sense indicating in special cases where evidence is available the more precise systematic position of the specimen4 ,the classification of ,cordaitean leaves proposed by ,grand',eury#eei is based partly on the form of the lamina and in part on the equality or inequality of the #8veins4' ,the actual veins1 which are embedded in the fairly thick mesophyll1 do not directly affect the superficial ribbing on the carbonised impression of the leaves and1 as seen in fig4 #dfe1 the most prominent hypodermal strands of supporting tissue which would appear as the main veins or primary ribs on an impression do not correspond in position with the vascular bundles4 ,although in some cases the largest stereome-strands coincide with the veins1 forming the upper and lower parts of ,i-shaped girders the centre of which is occupied by the veins1 this is by no means always the case4 ,grand',eury has drawn attention to the difference between the upper and lower surface of some carbonised leaves3 in ,c4 crassifolius 7fig4 #dfh1 ,d7#efj there are five to seven finer ribs between each pair of primary ribs on one face while the other shows ridges and grooves with a rib corresponding to each4 ,attention is called on a later page to the variable character of the ribbing even on different parts of the same lamina4 ,the lower surface of the leaf1 seen in section in fig4 #dfe1 would show a number of approximately equal ribs1 or possibly primary ribs 7midway between the veins7 separated by two interstitial ribs1 while on the upper face there would be three rather smaller secondary ribs4 ,in a section of a leaf called by ,renault ,c4 crassus#efa1 a specific name used also by ,lesquereux#efb for an impression of a leaf originally described by ,goeppert as ,noeggerathia crassa1 there are deep stereome-strands between the veins next the lower epidermis alternating with single smaller strands1 while on the upper surface the hypodermal strands occur only immediately above the veins4 ,in a section figured by ,felix#efc from ,north ,germany as ,c4 robustus1 the hypodermal stereome forms continuous bands2 on the upper face the bands are uniform in thickness but next the lower epidermis they form a series of ribs4 ,grand',eury's subgeneric terms ,cordaites1 ,dory-,cordaites1 and ,poa-,cordaites have therefore very little value as regards differences in the ribbing of leaf-impressions3 the large size of leaves included in ,dory-,cordaites and the more acute apex of the lamina as compared with the obtuse apex of smaller leaves of ,cordaites are features of limited application and of minor importance as diagnostic characters4 ,the name ,poa-,cordaites is1 however1 usefully employed for the narrower linear leaves with an obtuse apex4 ,the structure of a ,cordaites leaf is clearly shown in fig4 #dfe2 the lamina is approximately #a mm4 thick and there are about #cj veins in a breadth of #b cm4 ,strong ,i-shaped girders with the webbing composed of thick-walled cells divide the mesophyll into rectangular compartments3 the intervening hypodermal strands differ in number and size on the two faces4 ,the epidermis is not preserved3 specimens of other leaves show that the stomata#efd occur in rows on the lower surface4 ,the mesophyll shows no differentiation into palisade and spongy parenchyma1 and in this respect the leaf agrees with many other forms2 but in some leaves the palisade-tissue is well developed1 as in ,c4 lingulatus ,ren4#efe ,the central region of the lamina consisted of lacunar tissue1 portions of which are preserved1 with a more compact sheath of parenchyma enclosing each vein4 ,in some leaves there is a narrower sheath of thick-walled cells more sharply contrasted with the mesophyll4 ,the vascular bundles agree in structure with those in the rachis of a ,cycadean frond more closely than with the veins of an ,araucarian or other ,coniferous leaf4 ,the xylem consists mainly of centripetal elements which form a deltoid strand with the protoxylem at the apex1 and in close association with this is a larger or smaller amount of narrower centrifugal tracheids3 in the section shown in fig4 #dfe the centrifugal xylem may extend all round the centripetal tracheids1 but it usually forms an irregular arch with its base attached to the sides of the larger tracheal strand1 cp1 separated1 except at the base of the arch1 by a small amount of conjunctive parenchyma from the centripetal xylem4 ,the phloem is not preserved and is represented only by a few patches1 ph1 below the centrifugal tracheids4 ,dr ,benson#eff in her account of this type of leaf gives additional details and compares the anatomical features with those in other species4 ,the dual nature of the xylem like that characteristic of recent ,cycads has usually been regarded as a definite feature of ,cordaites leaves2 ,dr ,stopes1 on the other hand1 interprets the narrower tracheids 7occupying a position similar to those in fig4 #dfe7 in some sections of a leaf identified with ,c4 principalis from ,grand' ,croix1 as an inner sheath of transfusion elements 7#8primitive transfusion tissue'7 possibly derived from the centripetal xylem with which it is clearly connected at the sides precisely as in fig4 #dfe2 but in the ,grand' ,croix leaf the phloem is enclosed within the sheath of narrower tracheids and not external to it as it is in the section shown in fig4 #dfe and in a section of ,c4 lingulatus figured by ,dr ,stopes4 ,it is1 however1 difficult to recognise any fundamental difference between the #8inner transfusion tissue' and centripetal xylem4 ,the cells of the outer sheath in ,dr ,stopes's specimens of ,c4 principalis have bordered pits on their walls and this character is mentioned also by ,renault in other specimens4 ,illustration3 ,fig4 #dfe4 ,cordaites leaf 7,cordaites ,felicis ,bens471 probably borne on a ,mesoxylon stem4 cp1 centripetal xylem2 ph1 phloem2 px1 protoxylem4 7,kidston ,coll4 ,no4 #baid47 ,prof4 ,lignier#efg has described the structure of fragments of adult leaves from the ,stephanian of ,grand' ,croix 7,loire7 which he refers to ,cordaites lingulatus1 and the same author gives an interesting account of the anatomical features of a bud of the same species4 ,the bud1 which resembles in general appearance that of ,dolerophyllum 7fig4 #dcj1 p4 #acc7 is #c cm4 long1 oval in transverse section--as the result of compression--and consists of four convolute leaves and a piece of a fifth4 ,the outer leaves have #ge to #hj veins3 the inner laminae are sinistral in their curvature while the three outer leaves are dextral4 ,in the second1 the first in which the tissues are recognisable1 the small desmogen-strands afford some evidence that the phloem preceded the xylem in the order of differentiation as is often the case in recent plants4 ,the first tracheids occur almost in the centre of the desmogen-strand and to these are added the other tracheids of the centripetal xylem1 the oldest elements being spiral1 the next scalariform and the later tracheids reticulate4 ,the centrifugal xylem is formed at a later stage1 and at about the same time are differentiated the elements called by ,dr ,stopes the inner sheath and by ,lignier the #8bois diaphragmatique4' ,lignier also describes the development and structural features of the other tissues of the young leaves and compares the anatomical features of the ,french leaves with those of ,cordaites ,felicis described by ,prof4 ,benson4 ,the main features of ,cordaites leaves are 7i7 the presence of two kinds of xylem in the veins1 the larger centripetal tracheids1 or chief water-conducting elements1 and the narrower tracheids1 in some cases attached to the sides of the centripetal xylem1 in others forming free groups1 usually between the protoxylem and the phloem1 but sometimes enclosing the phloem2 7ii7 the frequent presence of a well-defined sheath of cells round each vein composed of comparatively thick-walled elements comparable with the transfusion-tracheids in ,conifers2 7iii7 the presence of lacunar tissue in the centre of the mesophyll and in some cases of transversely extended tracheids similar to those in some ,podocarp leaves2 7iv7 a well-developed system of stereome-strands and ,i-shaped girders4 ,the structural features on the whole suggest a xerophilous type1 and the frequent absence or feeble development of palisade tissue points to diffused rather than to brilliant sunlight4 ,the considerable range in size and form among ,cordaitean leaves as well as the obvious dependence on conditions of preservation or growth of such a relatively unimportant feature as the presence or absence of the so-called false or interstitial veins--the variability of which has been demonstrated in several instances--renders specific determination exceedingly difficult4 ,the following species are briefly described rather with a view to illustrate the nature of the characters employed by authors than as implying the existence of so many well-defined types4 ,cordaites principalis 7,germar74 ,this species was founded#efh on a large specimen from the ,coal ,measures of ,wettin showing a fan-like cluster of longitudinally torn and partially overlapping leaves spread out in the position that would be assumed on the compression of a shoot with a close spiral phyllotaxis4 ,this form of ,cordaites is the most abundant in the ,british ,coal ,measures4 ,the broadly linear lamina is characterised by an obtuse apex 7fig4 #dff1 ,a71 a tendency to split into strips1 close-set parallel ribs1 the stouter ribs or veins separated from one another by #b-c or it may be as many as #e finer ribs or interstitial #8veins4' ,a statement by ,weiss that in ,germar's type-specimen the longitudinal ribbing of the lamina is very imperfectly preserved confirms the scepticism that is justly felt as to the validity of this character as a satisfactory specific criterion4 ,illustration3 ,fig4 #dff4 ,a4 ,cordaites principalis1 part of leaf4 ,b4 ,artisia transversa1 pith-cast4 ,c4 ,cordaites principalis1 branch with leaf-scars4 7,a1 nat4 size2 ,b1 ,c1 nat4 size2 ,kidston ,coll47 ,the incomplete example shown in fig4 #dff1 ,a1 is #aie cm4 long and has a maximum breadth of #ce cm41 but the complete leaf was much larger and tapered gradually to the comparatively broad and slightly concave or amplexicaul base4 ,the narrow elliptical proximal end of a specimen figured by ,kidston#efi from the ,middle ,coal ,measures of ,yorkshire is #bh cm4 broad indicating that the tangentially expanded leaf-scars on a branch recently deprived of its foliage must have been a conspicuous feature4 ,in his synonymy of this species ,kidston#egj includes ,knorria taxina1 a species founded by ,lindley and ,hutton#ega on a piece of stem from the ,coal ,measures of ,newcastle4 ,the type-specimen1 as ,mr ,howse#egb states1 is much larger than the published drawing and closely resembles in the decurrent leaf-bases with broad apices the piece of stem represented in fig4 #dff1 ,c1 which ,kidston identifies as ,c4 principalis4 ,geinitz#egc refers to this species the seeds named ,cordaicarpus ,cordai 7,gein471 but there is no evidence of connexion4 ,kidston#egd points out that this seed is rare in ,britain3 he believes that ,cordaianthus ,pitcairniae 7,lind4 and ,hutt47 is probably the inflorescence of ,c4 principalis4 ,cordaites principalis occurs in both ,carboniferous and ,permian strata4 ,the leaves described by ,lesquereux#ege from ,pennsylvania as ,c4 ,mansfieldi agree closely with ,c4 principalis4 ,another similar or possibly identical form is represented by ,c4 ,ottonis ,gein4#egf ,cordaites borassifolius 7,sternberg74 ,the leaves of this species1 originally referred to ,flabellaria#egg1 resemble those of ,c4 principalis but differ in the ovate-lanceolate and less obtuse apex and in the presence of only one or rarely two finer striations between the stronger ribs4 ,corda's drawing#egh affords a good illustration of the crowded spiral disposition of the foliage comparable with that on an ,agathis shoot4 ,the lamina is usually #d-h cm4 broad but in exceptional cases may reach a breadth of #ab cm4 ,the species occurs in the ,coal ,measures1 especially in the ,westphalian series and in ,permian rocks4 ,feistmantel#egi unites with this type ,cordaianthus ,pitcairniae 7fig4 #dhj1 ,a71 but as in other cases there may be a confusion between ,c4 borassifolius and ,c4 principalis4 ,leaves described by ,lesquereux as ,c4 communis#ehj are1 as ,white says1 not distinguished by any well-marked characters from this species4 ,white#eha figures some good examples of ,c4 borassifolius from ,missouri1 reaching in one case a length of #dj cm41 showing on the lamina the fructifications of a fungus1 ,hysterites cordaitis#ehb ,grand',eury4 ,the leaves described from ,canada and the ,united ,states as ,c4 ,robbii#ehc ,daws4 are closely allied to if not identical with ,sternberg's type4 ,among other species differing in no definite character from ,c4 borassifolius is ,c4 lancifolius described by ,schmalhausen#ehd from the ,permian of ,russia4 ,cordaites lingulatus ,grand',eury4 ,the leaves of this species#ehe are characterised by the obovate lamina and bluntly rounded or almost truncate apex2 it affords a good illustration of the uncertainty of the ribbing as a diagnostic character4 ,the lamina of a well-preserved specimen from the ,blanzy coalfield described by ,zeiller#ehf reaches a length of #ce cm4 and a breadth of #aj-aa cm4 decreasing to #d cm4 at the base 7fig4 #dfg74 ,in the lower part of the lamina ,zeiller describes the ribs as unequal in prominence1 the stronger ones being separated by #a-c finer ribs1 while in the middle and upper portions the ribs appear to be of equal size4 ,some of the finer ribs are due to folding of the lamina and are not represented1 as are the ribs due to the presence of stereome-strands1 by dark streaks in the detached cuticle4 ,illustration3 ,fig4 #dfg4 ,cordaites lingulatus4 7,after ,zeiller2 nat4 size47 ,reference has already been made to the anatomical features of leaves of this species described by ,lignier#ehg and other authors4 ,cordaites grandifolius ,lesquereux4 ,the leaves so named by ,lesquereux#ehh1 from the ,coal ,measures of ,pennsylvania1 are distinguished by the elongate cuneate lamina1 which reaches a length of #ch cm4 with a narrow base and a slightly rounded truncate distal end1 #af cm4 broad1 characterised by a few broad and shallow crenulations4 ,by contrast with some ,american specimens in ,dr ,kidston's collection ,lesquereux's figures convey an imperfect idea of the size of the leaf4 ,a large leaf from the ,coal ,measures of ,belgium described by ,cambier and ,renier as a new species of ,psygmophyllum1 ,p4 ,delvali#ehi1 is perhaps identical with the ,american type2 the lamina of sub-triangular form has approximately the same dimensions2 the veins are numerous and repeatedly forked4 ,the leaf is much longer than any known ,psygmophyllum and the veins are much more numerous than in ,p4 majus ,arb4#eij1 the largest representative of that genus4 ,palaeobotanists who have seen the type-specimen inform me that they have no doubt as to the ,cordaitean nature of the ,belgian specimens1 which may be designated ,cordaites ,delvali4 ,it is1 however1 not impossible that ,psygmophyllum and ,cordaites are allied genera3 our knowledge of the former is limited to unimportant characters4 ,cordaites 7,dory-,cordaites7 palmaeformis 7,goeppert74 ,this ,permian type1 originally described by ,goeppert#eia as ,noeggerathia palmaeformis1 is characterised by numerous slender veins3 according to ,weiss#eib there may be as many as #c-e in #a mm4 ,the leaf is broadly lanceolate2 it tapers gradually to an acute apex reaching a length of #hj cm4 and a breadth of #aj cm4 ,in habit the young foliage-shoots#eic resemble those of ,c4 principalis and ,c4 borassifolius4 ,grand',eury records the frequent association of ,samaropsis seeds with this species2 it occurs in ,upper ,carboniferous and in ,permian strata and is recorded from a few ,british localities4 ,cordaites 7,poa-,cordaites7 microstachys ,goldenberg4 ,weiss#eid first figured this species from drawings supplied by ,goldenberg at whose suggestion the name ,c4 microstachys was adopted4 ,the type-specimen consists of a slender axis bearing numerous narrow linear leaves and a few imperfect fertile axillary shoots4 ,a specimen is figured by ,kidston#eie from the ,upper ,coal ,measures of ,radstock3 it is a rare type in ,britain4 ,the species is readily distinguished from ,c4 principalis and similar forms by the narrow lamina which varies considerably in length1 rarely as long as #cj cm4 and not exceeding #a cm4 in breadth4 ,the apex is obtuse and the ribs are either equal in strength or #a-b finer striae may alternate with the stronger ribs4 ,the base of the lamina is #c-d mm4 wide and the leaf-scars have a slightly arched upper margin and an almost straight lower edge#eif4 ,the foliage of this species1 generally regarded as identical with ,c4 linearis ,grand',eury1 bears a close resemblance to that of the ,mesozoic genus ,phoenicopsis from which it is distinguished by the occurrence of the leaves in bunches4 ,c4 gracilis ,lesq4#eig is a similar type4 ,the shoot on which ,lesquereux founded his genus ,desmiophyllum#eih may perhaps be an example of ,poa-,cordaites4 ,poa-,cordaites tenuifolius ,schmal4#eii from the ,permian of ,russia may be identical with ,c4 microstachys4 ,as examples of other forms of leaf referred to ,cordaites1 though as in other cases without any proof of connexion with branches having the anatomical features of the genus1 reference may be made to ,cordaites circularis ,grand',eury#fjj from ,gard 7fig4 #dfh1 ,b7 and a smaller leaf from the same locality compared with ,c4 ,lacoei 7fig4 #dfh1 ,c7 ,lesq4 ,cordaites circularis is characterised by the almost orbicular lamina traversed by slightly spreading veins2 it recalls some of the larger ,cyclopteris pinnules of ,pteridosperm fronds and is indistinguishable from some leaves assigned to the genus ,dolerophyllum#fja4 ,illustration3 ,fig4 #dfh4 ,a1 ,cordaites root-system 7,rhizo-,cordaites72 ,b1 ,cordaites circularis leaf2 ,c1 ,cordaites sp41 cf4 ,cordaites ,lacoei2 ,d1 ,cordaites crassifolius1 upper and lower surface of leaf4 7,after ,grand',eury47 ,the species ,c4 ,lacoei was founded by ,lesquereux#fjb on some detached specimens #c-ab cm4 long and #ae-e cm4 broad2 it is by no means certain that a specimen referred by ,grand',eury#fjc with some hesitation to this species is ,cordaitean4 ,the generic name ,scuto-,cordaites was proposed by ,renault#fjd for a specimen from ,commentry consisting of a flattened branch bearing a few imperfectly preserved leaves4 ,the surface of the branch shows semicircular leaf-scars on decurrent1 spirally disposed leaf-cushions and bears a certain resemblance to a slender stem of a ,clathrarian ,sigillaria4 ,the leaves of the type-specimen of ,scuto-,cordaites ,grand',euryi appear to be broadly linear1 #ac cm4 long1 the breadth gradually increasing from the base3 a short distance from the proximal end the lamina is broken up into narrow segments2 the veins are #e mm4 apart with finer striations between them4 ,some specimens from ,pennsylvania made by ,dawson#fje the type of a new sub-genus and named ,dictyo-,cordaites ,lecoi agree in shape and arrangement with some species of ,cordaites1 but differ in an occasional anastomosis of the veins as in ,psygmophyllum flabellatum4 ,it is1 however1 impossible to determine the true nature of the fossils from the published figures4 ,cordaitean leaves from ,india1 the ,southern ,hemisphere1 and ,siberia4 ,noeggerathiopsis1 ,feistmantel2 ,rhiptozamites1 ,schmalhausen2 ,euryphyllum1 ,feistmantel4 ,cordaites aequalis ,goeppert4 ,cordaites 7,noeggerathiopsis7 ,hislopi 7,bunbury74 ,in #ahde ,goeppert#fjf instituted the species ,noeggerathia aequalis 7fig4 #dfi7 and ,n4 distans for incomplete broadly linear and obovate leaves1 from ,siberian ,permian strata1 having a contracted base and equal parallel veins4 ,the specimens so named are no doubt specifically identical4 ,goeppert's species ,n4 aequalis has recently been carefully investigated by ,zalessky#fjg who agrees with ,kosmovsky#fjh in identifying it with ,noeggerathiopsis ,hislopi 7,bunb47 and ,rhiptozamites ,goepperti ,schmal4 ,schmalhausen#fji had previously pointed out the probable identity of his species with ,noeggerathia palmaeformis ,goepp4 7 ,cordaites74 ,the question of specific identity of these leaves from different localities and of other hardly distinguishable forms is of secondary importance2 the main point is that they are all examples of ,cordaitean leaves1 ,cordaites or some allied genus1 and point to the existence of this group of ,gymnosperms during ,permo-,carboniferous times in ,siberia1 ,china1 ,india1 ,australia1 ,south ,africa1 and ,s4 ,america1 also in the ,rhaetic floras of ,tonkin#faj and ,mexico#faa4 ,the fragments from ,devonian strata at ,iguana ,creek1 ,australia1 named by ,mc,coy#fab ,cordaites australis are probably pieces of the rachis of some large frond4 ,illustration3 ,fig4 #dfi4 ,a-,c1 ,e1 ,cordaites aequalis2 ,d1 ,cordaites ,clerci4 7,after ,zalessky2 nat4 size47 ,wieland#fac recently discovered ,cordaitean leaves exhibiting a wide range in size and shape in the ,mixteca flora of ,mexico in the lower members of a series which extends from the #8upper borders of the ,rhaetic' through the ,liassic to the lower beds of the ,inferior ,oolite4 ,these leaves are referred to ,noeggerathiopsis ,hislopi1 and it is clear from an examination of photographs received from ,dr ,wieland1 one of which is reproduced in fig4 #dgj1 that the ,mexican ,cordaites cannot be specifically distinguished from ,bunbury's type as represented by specimens described from ,india1 ,south ,africa1 ,siberia1 ,tonkin1 and elsewhere4 ,the occurrence of ,noeggerathiopsis is also recorded by ,newberry from the ,rhaetic series of ,honduras#fad4 ,noeggerathiopsis4 ,this genus was founded by ,feistmantel#fae for some leaves from ,lower ,gondwana rocks in ,india originally described by ,bunbury#faf as ,noeggerathia 7,cyclopteris87 ,hislopi 7figs4 #dgj-dgb7 and regarded by him as probably ,cycadean4 ,several authors have added to our knowledge of this widely spread southern type and in many localities the leaves occur in association with platyspermic seeds of the ,samaropsis or ,cordaicarpus type1 pieces of stems with ,cordaitean leaf-scars1 and petrified wood agreeing in the structure of the secondary xylem with that of ,european species of ,cordaites4 ,in some ,permo-,carboniferous sandstones at ,vereeniging1 ,south ,africa1 stumps and spreading roots 7fig4 #dgh7 resembling those described from ,france by ,grand',eury 7cf4 fig4 #dfh1 ,a7 have also been discovered4 ,a remarkable occurrence of roots and prostrate stems of some forest-tree was recorded some years ago in the bed of the ,vaal river near ,vereeniging where the surface of a seam of coal was exposed over an area of more than two acres#fag4 ,large branched roots 7fig4 #dgh7 spreading over the coal for a distance of several feet and thick stems #dj-ej ft in length with very few branches and but little decrease in diameter afford a striking picture of a forest-floor4 ,the frequent occurrence of ,cordaites 7,noeggerathiopsis7 ,hislopi in the associated strata suggests a reference of the stems and roots to that species4 ,moreover the structure of the secondary xylem of some petrified pieces of stem sent to me by ,mr ,leslie from ,vereeniging agrees closely with that of a ,european ,cordaitean stem4 ,illustration3 ,fig4 #dgj4 ,cordaites 7,noeggerathiopsis7 ,hislopi4 ,from ,mexico4 7,after ,wieland2 nat4 size47 ,illustration3 ,fig4 #dga4 ,cordaites 7,noeggerathiopsis7 ,hislopi4 ,from ,vereeniging4 7,a1 ca1 nat4 size2 ,b1 ca1 nat4 size47 ,illustration3 ,fig4 #dgb4 ,cordaites 7,noeggerathiopsis7 ,hislopi4 ,from ,india4 7,calcutta ,museum2 nat4 size47 ,the leaves of ,cordaites 7,noeggerathiopsis7 ,hislopi vary considerably in size1 in some cases reaching a length of #hj cm4 7fig4 #dga72 the lamina tapers gradually from a short distance behind the obtuse apex to a relatively narrow base3 in venation and form the leaves are very similar to those of ,c4 principalis and other ,european and ,north ,american species4 ,the specimen from ,india represented in fig4 #dgb shows several spathulate leaves attached in a close spiral to a branch4 ,as ,white#fah and ,zalessky have shown1 the stronger ribs are separated by less prominent striations indicating the presence of two sizes of hypodermal strands4 ,the obvious resemblance between ,noeggerathiopsis ,hislopi and species of ,cordaites has long been recognised and many authors have included ,feistmantel's genus in the ,cordaitales#fai4 ,prof4 ,zeiller#fbj preferred to retain the name ,noeggerathiopsis as a precautionary measure1 chiefly on the ground that the stomata appeared to be less definitely arranged in rows and more scattered than in the ,european leaves of ,cordaites1 and because of the absence of interstitial veins4 ,we have as yet little information as to the arrangement of the stomata1 but in view of the irregularity in stomatal grouping in recent leaves this feature is1 perhaps1 of minor importance4 ,the presence of interstitial #8veins' has now been established in ,indian#fba and ,south ,american#fbb leaves4 ,in a paper published in #aijhfbc the name ,cordaites was substituted for ,noeggerathiopsis and ,zalessky's recent work supports this step4 ,the description by ,zalessky of the ribbing in ,goeppert's species ,cordaites aequalis from ,siberia shows how uncertain and variable a character the venation is even in different parts of the same leaf4 ,cordaites ,clerci ,zalessky4 ,this species 7fig4 #dfi1 ,d7 was instituted for some small lanceolate or spathulate leaves from the ,petschora basin 7,adzva ,river7#fbd reaching a length of #f cm4 and a breadth of #a cm4 ,it is separated from ,cordaites aequalis on the ground that the veins are more numerous1 as many as #dd in a breadth of #a cm4 ,a recent investigation by ,miss ,holden#fbe of the carbonised cuticles of some ,indian specimens1 sent to ,cambridge by the ,director of the ,indian ,geological ,survey1 and a comparison of them with preparations made from ,european ,cordaites leaves1 have revealed certain distinguishing features which support ,zeiller's view that the ,gondwana-,land leaves1 though similar superficially to those of ,cordaites1 are probably distinct4 ,it is1 however1 impossible in many cases to obtain any information with regard to epidermal characters1 and though it would seem probable that had we a fuller knowledge of the ,indian and southern hemisphere plants represented for the most part by leaf-impressions well-defined distinguishing features would be recognised1 the comprehensive name ,cordaites may conveniently be retained on the ground that in the absence of well-preserved cuticles no satisfactory distinguishing features are exhibited by the impressions of ,noeggerathiopsis4 ,phylladoderma4 ,zalessky4 ,phylladoderma ,arberi ,zalessky4 ,zalessky#fbf founded this genus on some ,permian leaves from the ,petschora basin 7,adzva ,river7 which closely resemble those of ,cordaites but are characterised by a coarser venation4 ,the lanceolate lamina reaches a length of #ah cm4 and a breadth of #db cm42 the veins are #b mm4 apart and occasionally forked near the base of the leaf4 ,the epidermal cells have straight walls and stomata are abundant on the lower surface4 ,as ,zalessky says1 the systematic position of the leaves is uncertain though they are probably ,cordaitean4 ,the coarseness of the venation is a feature of minor importance and hardly worthy of generic recognition4 ,rhiptozamites ,schmalhausen4 ,this genus was instituted by ,schmalhausen#fbg for leaves from beds in the ,kusnezk basin regarded by him as ,jurassic4 ,these strata are now recognised as ,permian#fbh and homotaxial with those from which ,schmalhausen#fbi subsequently recorded the same species4 ,the leaves1 though smaller than many of the ,indian and ,south ,african specimens of ,cordaites 7,noeggerathiopsis7 ,hislopi1 may belong to that species4 ,zeiller and others definitely assigned the ,russian leaves to ,cordaites4 ,euryphyllum4 ,the ,indian leaves for which ,feistmantel#fcj proposed this name are1 as several writers have pointed out1 in all probability referable to ,cordaites4 ,the general conclusion to be drawn from this imperfect summary of an extensive literature is that the employment of the generic names ,noeggerathiopsis1 ,rhiptozamites1 ,euryphyllum1 and others has tended to exaggerate the difference between the ,european and ,southern botanical provinces during the ,permo-,carboniferous period4 ,scale-leaves1 seeds1 and stems4 ,the occurrence of small scale-like leaves of the type represented in fig4 #dfh1 ,c1 in association with ,cordaites 7,noeggerathiopsis7 ,hislopi#fca in ,india1 ,brazil1 ,siberia1 and elsewhere may mean that these organs are scales of large foliar buds4 ,the occurrence of several forms of platyspermic seeds1 in some cases apparently identical with ,european forms and sometimes distinct types1 in close association with ,cordaites 7,noeggerathiopsis7 ,hislopi has already been mentioned4 ,examples of such seeds are described in ,chapter xxxv4 under the genus ,samaropsis4 ,there are very few satisfactory examples of ,cordaitean branches from the southern hemisphere4 ,schmalhausen#fcb figures good specimens from ,siberian rocks from which his ,rhiptozamites leaves were obtained4 ,branches with spirally disposed leaf-scars figured by ,zeiller#fcc from the ,rhaetic of ,tonkin closely resemble ,cordaicladus4 ,feistmantel's drawing of a fossil from the ,karharbari series1 compared by him with a ,fern rhizome#fcd1 may be a ,cordaitean branch1 and the same author describes a stem#fce from ,new ,south ,wales as ,caulopteris ,adamsi which bears a close resemblance to a branch of ,cordaites4 ,similarly a leafy shoot described from ,india by ,zeiller as ,araucarites ,oldhami#fcf may be compared with branches of the ,poa-,cordaites type4 ,illustration3 ,fig4 #dgc4 ,cordaites 7or ,mesoxylon87 stem showing the discoid pith partially enclosed by wood4 7 nat4 size47 ,m4 ,s4 ,stems4 i4 ,pith-casts4 ,artisia4 ,sternberg4 ,a character to which authors tend to attach excessive importance as a diagnostic feature is the almost invariable tendency of the parenchymatous pith of ,cordaites to break up on contraction into transverse diaphragms1 thus producing what is known as a discoid pith4 ,in the stem shown in fig4 #dgc the pith is represented by a more or less cylindrical cast characterised by fairly regular transverse ribs and narrow grooves2 in the upper part of the fossil the peripheral tissue of the pith is preserved in the form of narrow plates projecting from the inner face of the wood4 ,as ,renault#fcg pointed out1 this type of pith is the expression of certain conditions of growth and is not a satisfactory distinguishing feature of any particular genus or family4 ,the same tendency to form a discoid pith is characteristic of ,mesoxylon1 and it occurs also in some other ,palaeozoic genera4 ,corda long ago figured a stem attributed by him to ,lomatofloyos with a typical discoid pith1 and a similar pith is recorded in a stem of ,dicranophyllum#fch4 ,among recent plants ,juglans regia affords perhaps the most familiar instance of an identical form of pith3 the same type occurs in the white ,jasmine1 in ,ceropegia peltata1 and some other flowering plants4 ,an interesting case is that of the tree ,groundsel1 ,senecio praecox ,d4,c4#fci1 of ,mexico3 in this plant1 which grows in arid districts1 the pith serves as a water-store and as the water is drawn off the thick turgescent discs contract and form thin transverse diaphragms separated by wide spaces1 as is also the case on drying in some succulent ,euphorbia stems4 ,it may be that in ,cordaites the medullary region also served as a water-reservoir and the depth of the medullary discs would vary according to the state of their contents4 ,the earlier writers regarded the pith-casts as stems with scars of amplexicaul leaves3 ,artis#fdj described specimens from the ,english ,coal ,measures as ,sternbergia1 one of which he stated to be #f ft long2 a few years later ,sternberg#fda proposed the name ,artisia and this has been generally used on the ground that ,sternbergia is the name of a recent flowering plant4 ,a specimen of ,artisia transversa 7,art47 from the ,coal ,measures of ,yorkshire is shown in fig4 #dff1 ,b1 and similar specimens varying considerably in diameter up to about #aj cm4 are abundant in ,european and ,american ,coal ,measures4 ,the prominence and depth of the transverse ridges1 the presence or absence of anastomoses between adjacent discs are1 as ,zeiller#fdb says1 of very doubtful value as specific characters4 ,dawson in #ahdffdc spoke of ,artisia as probably the pith of a tree1 a view suggested to him by ,mr ,dawes4 ,in #ahea ,williamson#fdd published a description of some specimens in which a pith-cast1 ,artisia approximata ,lind4 and ,hutt41 was enclosed by wood showing very clearly ,cordaitean characters4 ,further demonstration of the true nature of ,artisia was supplied by ,grand',eury from ,st tienne material4 ,if the generic name ,artisia is applied to all pith-casts showing the transverse ridges and grooves like those seen in fig4 #dff1 ,b1 it must be remembered that it is not safe to assume a connexion with ,cordaites or ,mesoxylon4 ,a ,liassic species described by ,lignier#fde from ,france as ,artisia alternans is quoted by authors as evidence of the persistence of ,cordaites into the ,jurassic period2 but in view of the fact that the discoid type of pith is not by any means confined to ,cordaites or even to the ,cordaitales the occurrence of ,artisia is in itself of no great botanical significance4 ,it is also true that a discoid pith is not an invariable attribute of stems closely allied to the genus ,cordaites2 but if these reservations are made the use of the generic term ,artisia serves a useful purpose4 ii4 ,petrified stems4 ,dadoxylon4 ,endlicher4 ,palaeobotanical literature contains numerous descriptions of ,palaeozoic petrified wood occasionally enclosing an ,artisia pith-cast described under such names as ,dadoxylon1 ,cordaioxylon1 ,araucarioxylon1 etc41 and regarded as portions of ,cordaitean stems4 ,it is1 however1 certain that much of this material belonged to stems other than those of ,cordaites4 ,recent research has demonstrated the insufficiency of the secondary xylem alone1 however well preserved1 as a safe guide to generic position3 stems identical in the structure of the secondary xylem differ in that of the primary portion of the stele1 and it is on the characters of the latter tissues that several genera have recently been founded4 ,mesoxylon affords a striking example of the importance of the primary xylem as a distinctive feature4 ,as ,gothan#fdf points out1 the species of ,calamopitys recently made the type of a new genus ,eristophyton#fdg would1 in the absence of the primary xylem1 probably be regarded as ,cordaitean4 ,it is important to recognise the limitations imposed by the imperfection of the material2 we cannot in most cases determine whether a specimen should be referred to ,cordaites or ,mesoxylon1 and while it may be described as probably ,cordaitean in affinity there remains the possibility that some of the ,palaeozoic plants with secondary wood like that of ,cordaites1 if their reproductive organs were known1 would not be included in the ,cordaitales4 ,goeppert's species ,araucarites ,tchihatcheffi1 which ,renault#fdh quotes as ,cordaites1 has recently been assigned to a new genus ,mesopitys#fdi because of certain distinctive features of the primary xylem4 ,additional examples might be quoted pointing to the tendency of recent and more thorough investigation to establish the fact that the occurrence of ,permo-,carboniferous wood of the ,araucarian type does not necessarily denote the existence of ,cordaites4 ,the question of nomenclature is necessarily raised in this connexion4 ,in recent years it has been customary to assign ,palaeozoic wood with ,araucarian pitting to the genus ,dadoxylon1 while wood of the same general type from more recent strata is by many authors referred to ,araucarioxylon#fej4 ,this arbitrary distinction based on a difference in age is open to serious objection4 ,fossil wood of the ,araucarian type is widely scattered in strata ranging from ,carboniferous to ,jurassic periods2 it also occurs in later formations4 ,the fact that on the one hand ,araucarian plants1 as recognised by cones and foliage-shoots1 are especially characteristic of ,jurassic floras and occur more rarely in ,rhaetic and ,triassic floras1 and on the other hand that ,cordaites and its allies reached their greatest development in ,permo-,carboniferous times1 renders it probable that in the majority of cases a distinctive name based on geological age would be in accordance with botanical differences4 ,but we have no satisfactory data as to the upper limits of the ,cordaiteae or the lower limits of the ,araucarineae3 in all probability the two families overlapped and co-existed for more than one geological period4 ,it is1 moreover1 the plants from formations where overlapping occurred that are the most critical from a botanical standpoint4 ,the age-distinction is therefore at best an artificial one and may be seriously misleading4 ,potoni#fea and ,gothan#feb have emphasised the desirability of adopting the name ,dadoxylon for all wood of the ,araucarian type irrespective of age4 ,if a particular specimen can be correlated definitely with ,cordaites or some other genus it should be so designated1 but the fragmentary nature of the records usually precludes this simple course4 ,the most logical plan is to use the name ,dadoxylon for all woods with ,araucarian characters if there is no sufficient reason for employing a less provisional term4 ,if the evidence clearly points to the ,araucarineae the generic name ,araucarioxylon should be added in parentheses after ,dadoxylon1 but whether or not this is done1 a statement as to the geological age of the fossil will in itself be some assistance in enabling the student to form an opinion on the balance of probability in favour of a ,cordaitean or an ,araucarian affinity4 ,the course suggested by ,gothan#fec1 namely to add ,cordaites after ,dadoxylon if an ,artisia pith is present1 is rendered inoperative now that we know that a discoid pith occurs in more than one genus4 ,in this chapter we are concerned primarily with ,cordaites and with such stems as may fairly be regarded as ,cordaitean3 examples of fossil wood from later formations are dealt with in another place4 ,a distinction between ,araucarioxylon and ,cordaioxylon stems has been based by ,felix on the nature of the pith-casts2 those of the ,artisia type he refers to ,cordaioxylon1 while ,palaeozoic stems with ,tylodendron pith-casts are assigned to ,araucarioxylon#fed4 ,this distinction can1 however1 only be made in the comparatively few cases in which the pith-cast is preserved4 ,its validity is1 moreover1 open to question4 ,a ,tylodendron 7 ,schizodendron7 cast shows on its surface the characters of the inner face of the secondary xylem1 projecting spindle-shaped areas representing the inner ends of medullary rays and a reticulum of grooves formed by the more resistant and prominent inner edges of the rows of tracheids 7fig4 #gdf74 ,a pith-cast of a stem in which the destruction by decay of the medullary parenchyma had not extended to the edge of the xylem-cylinder might show transverse diaphragms4 ,the occurrence of ,tylodendron casts means that decay had extended to the surface of the wood4 ,but in view of the occurrence of ,tylodendron casts in stems that are not those of ,cordaites a short account of the genus is given on another page#fee4 ,the main features of the stem of ,cordaites have already been enumerated4 ,the stele agrees with that of ,araucaria and ,agathis and especially with ,agathis in the double nature of the leaf-trace4 ,williamson#fef in #ahgg described pieces of wood from the ,english ,coal ,measures and the ,lower ,carboniferous of ,scotland which he referred to ,dadoxylon but without any specific name4 ,these include the ,coalbrookdale stem in which he had previously demonstrated the connexion between ,artisia and ,dadoxylon4 ,the structure of the xylem is like that in ,d4 ,brandlingii and the specimens may belong to that species4 ,the most interesting fact recorded by ,williamson is the occurrence of double leaf-traces1 a feature which led him to suspect a remote generic affinity to ,ginkgo4 ,this double trace may be an important diagnostic feature but unfortunately the majority of descriptions of species of ,dadoxylon throw no light on the character of the foliar bundles4 ,thomson and ,allin#feg have recently pointed out that a double leaf-trace occurs in a stem from the ,permian of ,kansas described by ,penhallow#feh as ,pityoxylon chasense and referred to that genus because of the supposed occurrence of resin-canals in some of the medullary rays3 the canals are apparently leaf-traces traversing broad rays in the secondary wood4 ,the primary xylem of ,cordaites is in direct continuity with the secondary tracheids and does not form mesarch strands as in ,mesoxylon4 ,the pith is usually discoid4 ,the pitting on the tracheids is a character of special importance3 while it is true to say that as a rule the number of pits on the radial walls of a single tracheid is larger than in the ,araucarineae1 this is not always the case4 ,in ,araucaria there are occasionally as many as five rows of alternate polygonal pits 7fig4 #fia1 ,a7 and in some ,palaeozoic ,dadoxylons there are only one#fei or two rows4 ,the very broad zone of transitional elements at the inner edge of the xylem-cylinder is a characteristic feature shared by the ,araucarineae#ffj2 the spiral protoxylem-tracheids are succeeded by scalariform elements and these1 by the gradual anastomosing of the transverse bars1 pass into tracheids with multiseriate pitting4 ,in this broad zone we probably have a primitive feature1 an epitome in a single stem of the course of development of multiseriate from scalariform pitting4 ,in some ,palaeozoic species with wood of the pycnoxylic type and agreeing generally with typical ,cordaites the bordered pits are sometimes separate and circular1 and opposite pits occasionally replace the usual alternate arrangement4 ,another feature on which stress has been laid is that in ,cordaites the pits occupy the whole breadth of the tracheal wall2 but this1 though frequently the case1 is by no means a constant feature4 ,in ,dadoxylon ,newberryi#ffa the pits tend to form groups1 leaving unpitted areas1 as in the genus ,coenoxylon#ffb4 ,in the stem of ,dadoxylon materiarum ,daws4 represented in fig4 #dge the pits do not always cover the whole of the tracheid-walls3 this stem is also instructive as an example of the different appearance presented by pitted tracheids according to the state of preservation4 ,in some places an oblique pore is well shown while in others only the outer border of the pit is seen4 ,gothan#ffc has described a specimen in which some of the pits are circular and occupy only the central area of the xylem elements3 separate circular pits occur also in ,d4 ,pedroi ,zeill4#ffd 7fig4 #dgf74 ,similar departures from the normal are illustrated by recent species of ,araucarineae4 ,the absence of a torus is another feature shared by ,dadoxylon and true ,araucarian wood4 ,annual rings other than incomplete and spasmodically formed rows of narrower tracheids are not as a rule present1 and in this respect also ,araucaria affords a close analogy4 ,thomson#ffe has figured a transverse section of a root from ,english ,coal ,measures in which rings of growth are well defined2 and other instances are recorded4 ,in an ,australian species named by ,arber ,d4 australe#fff1 there are well-marked rings of growth1 and this is equally the case in some ,indian wood#ffg of ,permo-,carboniferous age1 more nearly allied to ,mesoxylon than to ,cordaites1 and in a ,dadoxylon of similar age from ,south ,africa4 ,on the other hand the statement that annual rings occur in ,palaeozoic wood is often incorrect1 partial rings having been confused with regular concentric cylinders of summer elements4 ,dawson and ,matthew#ffh described rings in ,d4 ouangondianum1 and ,goeppert and ,stenzel#ffi1 who examined the ,canadian material1 refer to circles like annual rings2 but ,penhallow#fgj states that there is no evidence of true growth-rings4 ,the medullary rays are uniseriate and consist of thin parenchymatous cells with unpitted walls2 they vary considerably in depth1 usually comparatively shallow but in some cases #dj or #ej cells deep4 ,in recent ,araucarineae the rays are generally shallower4 ,the absence of special receptacles1 other than occasional resiniferous tracheids1 for products of secretion is a feature common to ,dadoxylon and the ,araucarineae4 ,the phloem presents no features of special interest1 but our knowledge of this tissue is comparatively meagre4 ,among other examples of large ,dadoxylon stems some of which no doubt bore ,cordaitean foliage--though as a rule we have insufficient information as regards anatomical characters to enable a decision to be made between ,cordaites and ,mesoxylon--reference should be made to the imposing array of silicified trunks in the grounds of the ,chemnitz ,museum#fga4 ,these were obtained from ,lower ,permian strata at ,hilbersdorf near ,chemnitz from beds overlain by porphyry tuff and resting on quartz porphyry1 the volcanic material which furnished the siliceous solutions4 ,several large pieces of wood were found in association with stems of ,medullosa and ,psaronius1 leaves of ,cordaites1 ,artisia pith-casts1 and ,cardiocarpus seeds with specimens of ,walchia1 ,gomphostrobus and other plants4 ,sterzel describes a stem #afe met4 long and #ae met4 in diameter2 on the main trunk the branch-scars are scattered but on some branches there is a tendency to a whorled arrangement4 ,this and many other stems are referred to ,araucarioxylon 7or ,dadoxylon7 saxonicum1 a species first described by ,reichenbach as ,megadendron saxonicum4 ,in one specimen ,sterzel states that the bordered pits are generally in #a-b rows1 though rarely in #c-d rows1 on the radial walls of the tracheids which they do not completely cover3 the medullary rays reach a depth of between #bj and #cj cells4 ,it is noteworthy that the stem #afe met4 long has a pith-cast of the ,tylodendron type4 ,dadoxylon 7,cordaites7 ,brandlingii 7,lindley and ,hutton74 #ahca4 ,pinites ,brandlingii ,lindley and ,hutton1 ,foss4 ,flor4 ,vol4 i4 ,pl4 i4 #ahej4 ,araucarites ,brandlingii ,goeppert1 ,foss4 ,conif4 p4 #bcb1 ,pls4 xxxix4-xli4 #ahij4 ,cordaioxylon ,brandlingii ,schenk1 in ,schimper and ,schenk1 p4 #hec1 fig4 #djh4 ,this species was founded on #8a fossil giant of the vegetable kingdom' discovered at ,wideopen near ,newcastle in ,carboniferous strata on the estate of ,mr ,brandling4 ,the stem1 #gb ft long and far from complete1 showed an irregular and not a whorled distribution of branch-scars4 ,it is noteworthy that in ,d4 medullaris 7,goepp47#fgb1 a ,permian species from ,saxony1 the branch-scars1 while for the most part irregularly scattered1 in one case showed an approach to a whorled disposition as in recent ,araucarias4 ,witham#fgc gave a fuller account of the structure of the stem than is included in the original description1 and the species has been described by many later authors from both ,permian and ,carboniferous localities4 ,the pith is discoid and the broad transitional region at the inner edge of the wood is a characteristic feature#fgd4 ,thomson#fge points out that there is a tendency to a retention of the scalariform type of pitting in the region of the medullary rays4 ,there are #a-e rows of pits on the radial walls of the tracheids4 ,the rays may reach a depth of #dj cells2 they are usually one cell broad4 ,it has recently been shown that as many as six vascular strands#fgf may form one leaf-trace instead of the customary pair1 a feature suggesting comparison with ,metacordaites ,rigolloti ,ren4 with its five foliar bundles4 ,other species agree very closely with ,d4 ,brandlingii and it is impossible to determine with accuracy the precise specific limits of stems agreeing generally with this type2 but for the sake of emphasising the variation in anatomical structure it is worth while to draw attention to a few more or less divergent forms from different geographical areas4 ,dadoxylon protopityoides ,felix4 ,an interesting feature in this ,westphalian type from ,germany is the occurrence of transversely elongated pits on the tracheids#fgg associated with those of normal form closely simulating the pits in the xylem elements of ,protopitys4 ,dadoxylon nummularium ,white4 ,in this ,brazilian wood#fgh from ,permo-,carboniferous beds the medullary rays are very numerous1 mostly uniseriate and #a-cj cells in depth4 ,the pits on the tracheids are in #a-b rows and are often contiguous4 ,in another type1 ,d4 meridionale1 described by the same author#fgi1 the pits are strictly uniseriate and generally contiguous4 ,as ,white says1 the absence of the pith and cortex and of any evidence as to the structure of the primary xylem renders impossible any definite expression of opinion as to the affinity of these and many other species4 ,dadoxylon ,nicoli ,seward4 ,dr ,arber#fhj in naming this species1 from the ,newcastle 7,permo-,carboniferous7 ,series of ,new ,south ,wales1 ,dadoxylon australe1 does not mention ,cri's earlier account of some wood from ,new ,caledonia under the name ,araucarioxylon australe#fha4 ,the latter generic name according to the usage adopted in this volume should be superseded by ,dadoxylon1 and this necessitates a fresh specific name for ,arber's specimens4 ,the name ,nicoli is suggested in place of australe1 as the sections on which ,arber founded his species form part of the ,nicol collection in the ,british ,museum4 ,the xylem shows distinct rings of growth1 a feature also seen in ,indian stems of approximately the same geological age and recorded by ,shirley#fhb in wood from ,queensland which needs more careful examination4 ,the bordered pits1 usually multiseriate and contiguous1 are not infrequently in #a-b rows and separate4 ,the uniseriate medullary rays are very numerous as in ,white's ,brazilian species ,d4 nummularium1 and as a rule #f-ab cells deep4 ,some well-preserved specimens from ,permo-,carboniferous strata in ,natal and ,zululand have been described by ,warren#fhc as ,dadoxylon australe ,arb41 showing interesting anatomical features1 but the material almost certainly includes more than one specific type and would repay more detailed investigation4 ,dadoxylon materiarum ,dawson4 ,this species was described by ,dawson#fhd from ,carboniferous strata in ,nova ,scotia and afterwards referred by ,penhallow#fhe to the genus ,cordaites4 ,in the transverse section reproduced in fig4 #dgd1 ,a1 the tracheid-walls have been reduced in thickness by partial decay1 but some of the bordered pits are clearly shown on the radial walls2 the pits usually form #b-d contiguous rows 7fig4 #dge7 in some cases with an oblique pore while others are represented either by the outer border of the pit or by the pore only4 ,the narrow medullary rays are as a rule uniseriate and may be #fj cells deep 7fig4 #dgd1 ,b74 ,dawson states that some specimens have large ,artisia pith-casts1 a fact that formerly would have been regarded as proof of the ,cordaites nature of the wood1 but in the absence of evidence with regard to the nature of the primary xylem it is impossible to say whether the stem is ,cordaites or ,mesoxylon4 ,dadoxylon sp4 ,some wood received from ,mr ,leslie1 collected at ,vereeniging1 ,south ,africa1 in ,permo-,carboniferous rocks1 shows well-defined rings of growth4 ,the pits form either a single row1 a double1 alternate and contiguous row1 or rarely three series on the tracheid walls4 ,the medullary rays are usually uniseriate and #a-cj cells deep4 ,dadoxylon ,kayi ,arber4 ,this species is represented by some large trunks1 in some cases with a diameter of #dj cm41 discovered by ,mr ,kay in the ,coal ,measures of ,worcestershire#fhf4 ,the pith is very small and shows no indication of a discoid structure1 but owing to its poor preservation no sections could be obtained of this region4 ,the secondary wood is characterised by the large number of uniseriate medullary rays #a-bg cells in depth2 the tracheids have usually two or sometimes three rows of alternate and contiguous bordered pits on the radial walls4 ,arber regards the absence of a discoid pith as a fatal objection to a reference of the stems to ,cordaites and speaks of them as affording further evidence of the occurrence of ,coniferae in the higher ,coal ,measures of the ,midlands4 ,it is1 however1 impossible to determine the position of the species in the absence of any data with regard to the structure of the perimedullary region1 and without such information we are hardly justified in regarding ,dadoxylon ,kayi as a member of the ,coniferales4 ,illustration3 ,fig4 #dgd4 ,dadoxylon materiarum4 ,transverse 7,a7 and tangential 7,b7 sections of the secondary xylem4 7,kidston ,coll4 #bbb1 #bbd47 ,illustration3 ,fig4 #dge4 ,dadoxylon materiarum4 ,a-,c radial longitudinal sections of the secondary xylem4 7,kidston ,coll4 #bbe47 ,dadoxylon ,pedroi ,zeiller4 ,this species from ,upper ,carboniferous or possibly ,lower ,permian strata in ,brazil#fhg has a pith #ch cm4 in diameter composed of parenchyma with scattered secretory sacs and characterised by the occurrence of three equidistant bays projecting into the cylinder of wood 7fig4 #dgf1 ,a7 which extend through the length of the specimen 7#f cm473 these1 as ,zeiller suggests1 may be connected with the departure of leaf-traces or branches4 ,the xylem is entirely composed of centrifugal elements and shows a broad transitional zone 7fig4 #dgf1 ,b7 including spiral1 scalariform1 and reticulate tracheids1 but the bordered pits are less numerous and less crowded than in many species of ,dadoxylon4 ,the rays are #a-b cells broad and reach a depth of #ej cells4 ,the most striking features are the solid and not discoid pith with its three rounded bays and secretory canals1 also the smaller number and frequently circular form of the pits on the tracheids4 ,zeiller considers that the stem is that of some ,cordaitean plant though probably not a true ,cordaites4 ,white#fhh questions the advisability of adopting the generic name ,dadoxylon and suggests the possibility1 though without any satisfactory evidence1 that it is the stem of a ,gangamopteris4 ,failing further information1 there would seem to be no sufficient reason for the institution of a distinctive generic name4 ,illustration3 ,fig4 #dgf4 ,dadoxylon ,pedroi4 ,a1 transverse section showing the pith and part of the secondary wood4 ,b1 longitudinal section of part of the secondary wood4 7,after ,zeiller47 ,dadoxylon permiense 7,renault74 ,this ,permian species from ,autun#fhi differs from typical examples of the genus in the differentiation of the pith into a central thin-walled region contracted into transverse diaphragms surrounded by a cylinder of stouter tissue and in the greater breadth of the medullary rays4 ,the tracheids have #c-d rows of pits of the usual type4 ,spirally disposed1 decurrent1 leaf-bases occur on the surface of the stem1 and the cortex includes secretory canals and strands of hypodermal stereome4 ,a small number of veins pass up the median part of the lamina which in this respect and in its greater thickness differs from that of ,cordaites leaves4 ,renault speaks of the rays as a cycadean feature1 but they are only two cells in width and shorter than in recent ,cycads4 ,dadoxylon spetsbergense ,gothan4 ,in this species#fij from ,spitzbergen1 of doubtful age though probably ,palaeozoic1 there is no xylem-parenchyma and the medullary rays are from #b to #e cells deep2 the bordered pits occur in #a-b or rarely #c rows on the radial walls of the tracheids2 they are alternate but not flattened and characterised by their small size 7#g high72 they do not cover the whole face of the tracheids4 ,it is pointed out that in many ,palaeozoic and ,mesozoic ,dadoxylons the pits are larger than in recent species 7#af-age as compared with #i-ab7 while in ,d4 spetsbergense they are still smaller4 ,the large size of the medullary-ray cells is another noteworthy feature1 also the absence of annual rings1 a character possibly connected with conditions of growth in northern regions4 ,it is1 however1 pointed out by ,nathorst#fia that the fossil was not found in situ and1 as he says1 it may have been carried by currents from a more southern locality4 ,metacordaites4 ,renault4 ,metacordaites ,rigolloti ,renault4 ,renault founded this species#fib and genus on a stem from ,autun which1 like ,d4 ,pedroi1 differs in certain respects from stems usually attributed to ,cordaites4 ,the pith is solid and contains secretory ducts and cells2 the tracheids have often a single row of pits1 and multiseriate pitting is much less common than in ,dadoxylon4 ,the medullary rays are generally #a-f cells deep4 ,a striking feature is the occurrence of groups of five vascular bundles penetrating the secondary wood in ,v-shaped groups1 each group being regarded as a multiple leaf-trace1 a type recently recognised by ,thomson in ,d4 ,brandlingii4 ,in one of ,renault's figures a larger scar1 presumably a branch-scar1 is shown immediately above a group of foliar bundles4 ,the genus ,metacordaites is considered by its author to be intermediate between ,conifers and the ,cordaitales1 but nearer to the former4 ,this conclusion is1 however1 based on insufficient evidence1 as nothing is known of the reproductive organs4 ,roots4 ,in #ahga ,williamson#fic gave an account of a petrified plant from the ,lancashire ,coal ,measures which he named ,dictyoxylon radicans1 but he afterwards came to the conclusion that the specimens so named were portions of the subterranean axis of some other plant1 possibly ,asterophyllites1 and proposed a new generic term ,amyelon#fid4 ,in #ahgd he brought forward fresh evidence in support of connecting ,amyelon radicans with ,asterophyllites or ,sphenophyllum1 genera which ,williamson believed to be very closely related4 ,it has since been recognised that ,amyelon is the root of ,cordaites or of some closely allied member of the ,cordaitales4 ,our knowledge of ,cordaitean roots is based chiefly on the work of ,williamson and ,renault#fie1 and more recently ,osborne#fif has added new facts of considerable interest4 ,in the larger roots the primary xylem may be diarch or there may be as many as four or five protoxylem groups 7fig4 #dgg74 ,the primary tracheids are spiral or scalariform and the space1 s1 separating them from the surrounding secondary xylem seen in fig4 #dgg1 ,b1 was no doubt originally occupied by conjunctive parenchyma4 ,the secondary wood is composed of tracheids1 with contiguous bordered pits identical with those in the xylem of the stem1 and narrow medullary rays4 ,the section1 #d mm4 in diameter1 represented in fig4 #dgg1 ,a1 shows a tetrarch primary xylem strand enclosed by secondary wood composed of rather thin-walled elements succeeded by a zone of phloem including some secretory sacs1 and beyond this is a cylinder of periderm1 p4 ,in a section of a root figured by ,renault from ,autun the periderm is separated from the stele by a broad band of parenchyma which appears to be cortical1 but in the ,british specimens the deep-seated origin of the periderm is clearly shown3 ,osborne states that it arises in a layer immediately outside the endodermis4 ,in one of the specimens figured by ,williamson#fig the secondary wood shows clearly marked irregular concentric lines simulating rings of growth1 but there is no evidence of any regularly recurring variation in the diameter of the xylem-elements4 ,from the descriptions of ,williamson and ,osborne it is evident that the roots of ,cordaites were profusely branched and1 as the latter author has shown1 the method of branching points to the formation of coralline roots like those of recent ,cycads1 some ,conifers and ,dicotyledons4 ,osborne found that the cortex of small rootlets is composed of two zones1 an outer parenchyma without cell-contents and an inner parenchymatous tissue characterised by the occurrence in some of the cells of tangled masses of fungal hyphae almost always unseptate4 ,in some cases the hyphae bear terminal vesicles similar to those observed on fungal hyphae in the cortex of ,podocarpus roots4 ,osborne makes out a good case for regarding the fungus as symbiotically related to the tissues of the lateral roots1 a relationship identical with that in many existing trees1 particularly ,myrica and ,alnus4 ,it is suggested that the formation of the coralline root-tubercles is a feature consistent with the view that ,cordaites lived in saline marshes1 a physiologically dry habitat favourable to the occurrence of mycorhiza4 ,illustration3 ,fig4 #dgg4 ,a1 root of ,cordaites4 ,b1 centre of the root enlarged2 p1 periderm2 s1 space4 7,kidston ,coll4 #aijf47 ,illustration3 ,fig4 #dgh4 ,root 7,cordaites87 exposed in the bed of the ,vaal river4 7,after ,mellor and ,leslie47 ,reference has already been made to the habit of ,cordaitean roots in the general account of the genus 7figs4 #dfh1 ,a1 #dgh74 ,the specimen shown in fig4 #dgh may be a root of ,cordaites 7,noeggerathiopsis7 ,hislopi1 but nothing is known as to its structure#fih4 ,reproductive ,organs4 ,cordaianthus4 ,grand',eury4 ,we have as yet no definite knowledge of the nature of the reproductive organs of ,mesoxylon and ,poroxylon1 but having regard to their close resemblance in other respects to ,cordaites1 particularly in the case of ,mesoxylon1 the presumption is that some of the seeds and fertile shoots attributed to ,cordaites may belong to other members of the ,cordaitales4 ,despite the abundance of ,cordaites1 or at least of material assigned to that genus1 and the comparative frequency of fertile shoots in actual connexion with foliage-shoots1 the practical identity of ,mesoxylon and ,cordaites leaves precludes any confident use of the latter name in a strict sense4 ,in #ahbb ,brongniart#fii described a small bud-like fossil of ,tertiary age as ,antholithes liliacea1 and this generic name in the form ,antholithus became widely used for fertile shoots or flowers from different geological horizons4 ,as knowledge became more precise other names replaced ,antholithus1 though ,renault#gjj retained it for some inflorescences from ,commentry which could not definitely be included in ,cordaites4 ,lindley and ,hutton#gja employed the genus for a specimen1 now recognised as a ,cordaitean fertile shoot1 from the ,coal ,measures which they called ,antholithus ,pitcairniae1 the specific name being chosen to indicate a possible affinity to the ,bromeliaceous genus ,pitcairnia4 ,a few years later ,morris#gjb described a similar inflorescence as ,a4 anomalus4 ,in #ahgb ,carruthers#gjc substituted ,brongniart's term ,cardiocarpon for ,antholithus and called ,a4 ,pitcairniae ,cardiocarpon ,lindleyi and ,morris's species ,c4 anomalum4 ,the specific name ,lindleyi has been widely adopted1 but there would seem to be no adequate reason for disregarding the priority-rule4 ,it is1 however1 customary to use ,grand',eury's term ,cordaianthus for all ,cordaitean inflorescences4 ,goeppert#gjd suggested the name ,botryoconus for an inflorescence similar to ,c4 ,pitcairniae and for this ,c4 ,e4 ,weiss#gje substituted ,noeggerathianthus on the ground that he considered ,goeppert's specimen to be the male inflorescence of ,noeggerathia4 ,grand',eury resuscitated ,botryoconus#gjf for some spikes from the ,gard coalfield connected by him with ,dory-,cordaites4 ,the nature of the seeds borne by the inflorescences has largely influenced authors in the choice of a generic name3 ,carruthers used ,cardiocarpon while ,zeiller#gjg speaks of ,samaropsis ,pitcairniae4 ,the genus ,cardiocarpon was founded by ,brongniart for compressed cordiform seeds1 but it was not until later that their gymnospermous nature was recognised4 ,further reference to the nomenclature of seeds of the ,cardiocarpon type will be found in ,chapter xxxv4 ,the correlation by ,grand',eury and other authors of different species of inflorescences and species of ,cordaites is frequently based on association1 and in the absence of more satisfactory evidence the safer course is to deal with ,cordaitean fertile shoots in a general sense4 ,illustration3 ,fig4 #dgi4 ,cordaianthus4 ,from the ,middle ,coal ,measures of ,lancashire4 7,manchester ,museum2 nat4 size47 7a7 ,ovulate shoots4 ,these are represented by a considerable number of forms in both ,european and ,american localities4 ,in rare cases the compound shoot reaches a length of #cj cm4 7fig4 #dgi71 but it is usually much shorter2 the lateral compact buds may be more or less widely separated3 the seeds have long pedicels 7fig4 #dhj1 ,a7 or appear to be sessile 7fig4 #dhj1 ,b7 and there may be one or several seeds on a single lateral shoot4 ,the seeds are platyspermic and1 as seen in fig4 #dhj1 ,a1 in some inflorescences they show very clearly the ,samaropsis features4 ,it would1 however1 be unsafe to assume that all ,samaropsis seeds were borne on ,cordaitean plants4 ,among other types of seed referred by authors to ,cordaites are ,cardiocarpus1 ,cordaicarpus1 ,sarcotaxus1 ,taxospermum1 ,diplotesta1 and ,leptocaryon4 ,but in most cases there is no evidence of actual connexion between seeds and vegetative organs1 and while it is possible to state with confidence that many of the seeds represented by impressions described as species of ,samaropsis and ,cordaicarpus are undoubtedly ,cordaitean1 it is certain that not all seeds referable to these genera were borne by ,cordaitalean plants4 ,cordaitean seeds are characterised by certain morphological features recalling those found in recent ,cycads and in the seeds of ,ginkgo as illustrated by species of ,cardiocarpus and some allied types4 ,as most of the ,palaeozoic seeds known in a petrified state cannot be assigned to their parent-plants they are dealt with in a separate chapter#gjh4 ,cordaianthus ,pitcairniae 7,lindley and ,hutton74 ,this type of inflorescence#gji is considered by ,kidston to belong to the tree which bore leaves known as ,cordaites principalis1 but if this is the case it is probable that the stem possessed the anatomical characters of ,mesoxylon4 ,illustration3 ,fig4 #dhj4 ,a1 ,cordaianthus ,pitcairniae with ,samaropsis seeds4 ,b1 ,cordaianthus ,volkmanni4 ,b1 portion of ,b enlarged4 7,a1 ,b1 nat4 size2 ,kidston ,coll4 #bcgd1 #aagd47 ,the portion of an inflorescence shown in fig4 #dhj1 ,a1 from the ,middle ,coal ,measures of ,yorkshire1 illustrates the occurrence of the bud-like fertile shoots and the stalked ,samaropsis seeds4 ,a species described by ,renault#gaj from ,commentry as ,cordaianthus acicularis may be identical with the ,british species4 ,cordaianthus ,volkmanni ,ettingshausen4 ,the example of this species#gaa seen in fig4 #dhj1 ,b1 shows the relatively small size of the lateral buds1 presumably unexpanded1 compared with the large subtending bracts4 ,petrified specimens of ,cordaianthus4 ,our knowledge of the structure of ,cordaianthus is based on the researches of ,renault#gab1 supplemented by those of ,prof4 ,bertrand#gac to whose kindness ,i owe the photographs reproduced in fig4 #dha4 ,the inflorescences described by ,renault are referred by him to different species1 but in the following brief account these are treated from a generic standpoint4 ,the tangential section of ,cordaianthus ,williamsoni ,ren4 shown in fig4 #dha1 ,d1 was originally figured by ,renault and more recently by ,bertrand2 it shows the spirally disposed leaf-traces in the lower part of a stout axis1 and at the sides some vascular bundles are seen passing up into the bracts4 ,a very small proportion of the bracts subtend ovules2 two are seen at a and b1 and at c is the tangentially cut micropylar canal of a third borne near the apex and covered by the terminal cluster of bracts4 ,the ovule a1 separated by a narrow space from its short stalk1 consists of a thick single integument--not two as stated by ,renault--extended at the apex as a micropylar canal3 the apical extension is more completely shown in the tangentially cut ovule b4 ,the central body is much contracted and the two spaces1 s1 at the base are regarded by ,bertrand as cavities in the integument separated from one another by a central strand of conducting tissue which gives off two bundles to the integument1 one at each end of the long axis of the seed 7fig4 #dha1 ,a1 v74 ,the dark patch1 n 7fig4 ,d71 is the upper and broader end of the shrunken nucellus the apex of which extends upwards as a slender beak1 and this originally no doubt fitted into the micropyle4 ,fig4 #dha1 ,c1 shows a female inflorescence in transverse section2 the stele consists of a ring of bundles separated by broad medullary rays and enclosing a comparatively large pith3 the leaf-traces are seen in the cortex and one is cut through as it bends out into a bract which is not yet free from the axis4 ,two ovules1 seen in section at a and b1 are represented by the bilaterally symmetrical and compressed integument enclosing small pieces of nucellar tissue4 ,fig4 #dha1 ,e1 is a transverse section of an inflorescence at a higher level and above the apex of the axis3 there are four large ovules and one aborted ovule1 a4 ,bertrand describes two vascular bundles in the integument of the ovule a1 one at each end of the long axis4 ,illustration3 ,fig4 #dha4 ,a1 ,b1 ,cordaianthus ,grand',euryi1 ovule showing apex of nucellus1 ,b1 with microspores1 p2 pc1 pollen-chamber2 b1 beak of nucellus2 v1 vascular bundle4 ,c1 transverse section of flower-bud with ovules1 a1 b4 ,d1 ,cordaianthus ,williamsoni1 longitudinal section2 a-c ovules2 s1 spaces2 n1 nucellus4 ,e1 ,cordaianthus ,zeilleri1 transverse section showing four large ovules and one aborted ovule 7a72 v1 vascular bundle4 ,f1 transverse section of male flower2 m1 microsporangia4 7,from photographs supplied by ,prof4 ,bertrand47 ,fig4 #dha1 ,a1 ,b1 ,cordaianthus ,grand',euryi ,ren41 shows a longitudinal section of the nucellus1 #ae #g mm41 and part of the integument of an ovule at the time of pollination1 which was probably aided by the secretion of a drop of mucilage as in the ovules of recent ,conifers4 ,the integument1 separated by a broad space from the nucellus1 is cut in the plane of the two vascular strands1 v4 ,from the centre of its broad upper surface the nucellus projects upwards as a beak1 b1 and this originally engaged with the micropylar canal formed by the integument3 the lighter patch below the beak is the pollen-chamber 7fig4 #dha1 ,b1 pc7 containing two microspores1 and two more1 p1 are seen above the nucellar beak4 ,in another species described by ,renault1 ,c4 ,lacattii1 the nucellus fills the space bounded by the integument4 99 99 99 99 99 7b7 ,staminate inflorescences4 ,the male inflorescence1 though smaller1 is similar in habit to the ovulate shoot3 the secondary branch consists of a short axis bearing crowded1 spirally disposed1 bracts1 and the actual flowers are represented by single stamens or groups of #b-c highly specialised microsporophylls4 ,each microsporophyll consists of a long filament with a central vascular strand bearing at its apex #c-d long microsporangia 7fig4 #dha1 ,f1 m7 which open longitudinally as seen in fig4 #dhb1 ,a4 ,the microsporangia are #be-c mm4 long covered by dark palisade cells and thin-walled parenchyma1 shown as indistinct patches in the photograph4 ,some of the elliptical and comparatively large microspores are seen in fig4 #dhb1 ,b2 the exine is finely punctate and inside are the remains of a few thin cells in which presumably spermatozoids were developed4 ,the microspores shown in fig4 #dhb1 ,b1 have a maximum length of #ja mm43 ,renault describes some as #ji mm4 long while others are much smaller4 ,fig4 #dha1 ,f1 is a transverse section of a staminate inflorescence showing near the centre five groups of microsporangia1 each sporangium having the form of a curved incomplete dark band indicating that dehiscence has occurred4 ,illustration3 ,fig4 #dhb4 ,cordaianthus4 ,microsporangia1 ,a1 and ,microspores1 ,b4 7,university ,college ,collection1 ,london47 ,mesoxylon4 ,scott and ,maslen4 ,this generic name was instituted for stems obtained by ,messrs ,lomax from the ,lower ,coal ,measures of ,lancashire#gad previously referred by ,scott#gae to ,cordaites and ,poroxylon4 ,further investigation showed that while agreeing closely with those genera they possessed certain distinctive features demanding recognition4 ,the name chosen suggests the intermediate nature of the stems4 ,the more striking features may be summarised as follows3 ,in the largest specimens so far described the stem1 including leaf-bases1 reaches a diameter of #e or #f cm42 the large pith consists in the central region of diaphragms of parenchyma separated by horizontal spaces produced by splitting and shrinkage consequent on the failure of the tissue to keep pace with the general growth of the stem4 ,the secondary xylem is of the ,araucarian type and has narrow medullary rays varying in depth from #a to #be cells4 ,the leaf-traces are represented by twin-bundles which fuse in the downward direction1 the level at which fusion occurs being regarded as a specific character4 ,the presence of centripetal xylem is an essential feature of the traces3 the occurrence of single or double traces consisting of centripetal elements and1 externally1 a large amount of centrifugal xylem is an important feature in which ,mesoxylon differs from ,cordaites4 ,the double leaf-traces divide after emerging from the secondary wood and each strap-like leaf receives several collateral bundles 7fig4 #dhc1 ,c74 ,an axillary bud may occur at the base of each leaf 7fig4 #dhc1 ,a1 b74 ,the phloem1 including sieve-tubes and secretory sacs1 is succeeded by a broad pericycle1 and the comparatively narrow cortex is traversed by successive bands of periderm4 ,in the outer region of the cortex the presence of radial bands of fibres is a characteristic feature4 ,the reproductive organs are unknown4 ,the anatomical features are well illustrated by ,m4 ,sutcliffii first described by ,scott1 who provisionally placed it in ,poroxylon1 and afterwards more fully investigated by ,maslen#gaf4 ,mesoxylon ,sutcliffii ,scott4 ,the average diameter of the stem is #c cm43 the section reproduced in fig4 #dhc1 ,a1 has a maximum breadth of #ce cm42 the leaf-bases cut at different levels give an irregular contour to the surface like that of a ,lepidodendron4 ,an axillary bud1 either reproductive or vegetative1 is seen at b consisting of a short axis bearing crowded bud-scales4 ,the leaves are crowded and according to ,maslen have a phyllotaxis of 3 the lamina is linear like that of ,cordaites with #af collateral bundles in the petiole4 ,the presence of a meristematic band at the base of the lamina affords evidence of a deciduous habit4 ,the large size of the pith is a striking feature with its central tissues in the form of transverse diaphragms and a narrower peripheral zone of solid parenchyma 7fig4 #dhc1 ,a1 a74 ,the secondary wood of the stele is composed of tracheids with #b-c contiguous alternate rows of bordered pits on the radial walls1 but none on the tangential walls4 ,in the stem shown in fig4 #dhc1 ,a1 the secondary wood is preserved only in patches4 ,numerous blunt teeth varying in prominence project into the pith2 these consist chiefly of serially disposed centrifugal tracheids distinguished by their spiral and scalariform structure and by the medullary rays which are broader than those in the more external xylem4 ,further reference is made to these perimedullary strands in the description of the leaf-traces4 ,the medullary rays are uniseriate and usually #a-f cells in depth3 beyond the secondary wood is a cambium and a cylinder of secondary phloem 7fig4 #dhc1 ,d1 ph7 consisting of tubular elements1 presumably sieve-tubes1 and elongated secretory sacs4 ,the pericycle is composed of several rows of rather large and short cells and has an ill-defined outer boundary4 ,a succession of arcs of periderm-like tissue and phellogen1 which may invade the pericycle and phloem1 forms a prominent feature in the cortex2 radially placed bands of fibres similar to those in ,lyginopteris and other genera occur in the outer cortex4 ,at the edge of the pith the more prominent projections of xylem are arranged in pairs 7fig4 #dhc1 ,b7 and as each pair travels downwards the component strands gradually fuse#gag4 ,each bundle of a double trace consists internally of an arc of centripetal xylem1 the elements of which are arranged in rows 7fig4 #dhc1 ,b1 cp71 with a single protoxylem group in the middle of the inner face1 px4 ,it is not clear whether any primary centrifugal tracheids are present1 but there are indications that such are occasionally represented4 ,in most cases the primary xylem of the leaf-traces is exarch1 but the existence of mesarch bundles is not improbable4 ,the bulk of each foliar bundle is formed of a fan-shaped mass of secondary centrifugal xylem 7fig4 #dhc1 ,b1 cf7 and an island of parenchyma occurs next the protoxylem4 ,there is no clearly defined boundary between the outer or centrifugal xylem of the leaf-traces and the tracheids of the stem-wood2 the latter may consist exclusively of tracheids with bordered pits or the inner rows of the xylem-cylinder may be of the scalariform or spiral type4 ,differences shown in transverse sections of the inner portion of the xylem are due to the circumstance that in certain parts of the inner face of the secondary wood leaf-traces are unrepresented1 while in other places the dwindled remains of the outer1 centrifugal1 portions of a trace are still recognisable4 ,as each double leaf-trace passes down the pith the bundles fuse and the single strand retains for a time some centripetal xylem2 this gradually disappears and at a lower level the centripetal xylem also dies out4 ,the space enclosing the obtuse apices of the bundles shown in fig4 #dhc1 ,b1 was originally occupied by thin-walled tissue which accompanied the trace in its outward course4 ,in ,mesoxylon ,sutcliffii the leaf-strands pass almost horizontally through the secondary wood1 bend outwards in the phloem and follow a steeply ascending course to the leaves4 ,in fig4 #dhc1 ,b1 a double leaf-trace is seen at the inner edge of the secondary wood with the centrifugal xylem1 cf1 continuous with that of the stele3 fig4 #dhc1 ,d1 lt1 shows a leaf-trace in the pericycle where one of the bundles has divided and the other is tangentially extended and partially divided4 ,the branching is carried further in the cortex1 as seen in fig4 #dhc1 ,c1 where the trace is represented by a curved row of six bundles1 lt1 and at a higher level further subdivision may occur4 ,the leaf-bundles are collateral and in the leaf retain both centripetal and centrifugal tracheids4 ,in the section shown in fig4 #dhc1 ,c1 the oval stele of an axillary shoot is seen at s subtended by the row of collateral bundles3 the stele has a fairly large pith surrounded by a zone of secondary xylem with broad medullary rays4 ,illustration3 ,fig4 #dhc4 ,mesoxylon ,sutcliffii4 ,transverse sections of stem4 ,a4 a1 outer pith2 b1 axillary bud2 x secondary xylem4 ,b4 cp1 cf1 centripetal and centrifugal xylem2 px1 protoxylem4 ,c4 lt1 leaf-traces in the cortex2 s1 stele of axillary branch2 ph1 secondary phloem4 ,d4 ,leaf-trace bundles1 lt1 external to the phloem1 ph4 7,a1 ,c1 ,d1 sections in the ,manchester ,collection1 #gag b2 ,b1 ,cambridge ,botany ,school1 #ecj47 99 99 99 99 99 ,among other species of ,mesoxylon mention may be made of ,m4 ,lomaxi and ,m4 poroxyloides4 ,m4 ,lomaxi ,scott and ,maslen#gah generally resembles ,m4 ,sutcliffii but shows the following distinctive features3 the leaves are more scattered and less crowded2 the twin-bundles of the leaf-traces fuse immediately on entering the pith1 thus appearing for the most part as single and not double strands in the perimedullary zone2 the centripetal xylem is well developed1 the medullary rays are deeper and the outer cortex has shorter bands of mechanical tissue4 ,in ,mesoxylon poroxyloides ,scott and ,maslen#gai1 the twin-bundles of the traces unite soon after reaching the pith as in ,m4 ,lomaxi1 the secondary tracheids have only two rows1 or sometimes a single row1 of bordered pits and the tracheids are rather smaller than in ,m4 ,lomaxi 7#bj-dj as compared with #cj-fj7 and the medullary rays are shallower4 ,there is a particularly broad zone of spiral and reticulate transitional tracheids at the inner edge of the wood as in ,cordaites and in ,dadoxylon ,pedroi 7fig4 #dgf74 ,the leaves of this species are believed to be represented by the type described by ,dr ,benson as ,cordaites ,felicis 7fig4 #dfe7gbj1 but1 as already suggested1 it is very probable that many or possibly nearly all the leaves from ,british ,coal ,measures described as ,cordaites may belong to ,mesoxylon4 ,the chief interest of the genus ,mesoxylon is its close resemblance in certain characters to ,cordaites and ,poroxylon3 the presence of strands of centripetal xylem in the perimedullary region is an important feature in which ,mesoxylon differs from stems assigned 7under the generic name ,dadoxylon7 to ,cordaites4 ,mesoxylon differs from ,poroxylon in having a discoid pith like that of ,cordaites1 but a more important difference is the absence in the leaf-trace xylem of ,mesoxylon of bordered pits of the ,araucarian type1 whereas in ,poroxylon ,araucarian pits occur in both the centripetal and centrifugal tracheids4 ,in ,poroxylon the secondary xylem is manoxylic2 in ,mesoxylon1 as in ,cordaites1 it is pycnoxylic4 ,the range of ,cordaites and a consideration of other imperfectly known genera4 ,an increased precision in knowledge derived from anatomical investigation often tends to demonstrate the untrustworthiness of criteria based on external features previously employed with confidence4 ,this inevitable though1 from the point of view of the systematist1 inconvenient result of intensive study is well illustrated by the recent discovery of the stems named by ,scott and ,maslen ,mesoxylon#gba4 ,a separation of ,cordaites from ,mesoxylon1 which no doubt extended far beyond the ,british area1 is possible only if well-preserved petrified material is available4 ,the leaves of ,mesoxylon1 so far as our imperfect knowledge of them enables us to express an opinion1 are constructed on a plan almost identical with those of ,cordaites and1 as already stated1 it is almost certain that many of the impressions referred to ,cordaites were borne on ,mesoxylon stems4 ,an additional source of confusion is supplied by the ,cordaites-like leaves of ,poroxylon4 ,it is evident1 therefore1 that even within the limits of the ,carboniferous and ,permian formations the recognition of true ,cordaites leaves must often be attended with considerable risk of error4 ,apart from the possible confusion between the foliage of ,cordaites and ,mesoxylon there are other difficulties as regards detached leaves which depart more or less widely from the typical ,cordaitean form4 ,leaves such as ,c4 circularis 7fig4 #dfh1 ,b7 and ,c4 grandifolius emphasise the lack of any thoroughly satisfactory dividing line separating single pinnules of ,cardiopteris or ,cyclopteris on the one hand and leaves of ,psygmophyllum on the other from ,cordaites4 ,the petrified buds described as ,dolerophyllum#gbb have been quoted by several authors as examples of unexpanded shoots of ,cordaites though anatomical evidence warrants a generic separation4 ,in the case of species founded on leaves described in this chapter as ,cordaites it should be remembered that further research may necessitate an alteration in nomenclature4 ,among the species included in ,cordaites is ,noeggerathiopsis ,hislopi#gbc 7figs4 #dgj-dgb71 a type widely spread in ,india and in other parts of ,gondwana-,land3 if the change of generic name is accepted it involves the extension of the geographical range of ,cordaites from ,northern ,europe and ,north ,america to the southern botanical province4 ,we have as yet no proof of the existence of ,cordaites in the ,arctic regions4 ,the range in time of ,cordaites or of the ,cordaitales has generally been stated to be from the ,upper ,devonian to the ,permian4 ,it is1 however1 by no means certain that the genus flourished before the ,carboniferous period1 though it is clear that closely allied types must have lived in pre-,carboniferous floras4 ,the strata in ,new ,brunswick from which ,dawson recorded his supposed ,devonian ,cordaites have been shown to be ,upper ,carboniferous in age#gbd4 ,as regards the length of time during which the ,cordaitales existed we have no decisive evidence4 ,in recent years the tendency has been to extend their range into the ,mesozoic era1 and there are several pieces of evidence in favour of this4 ,there is no doubt that considerations of age based on the arbitrary divisions of the geological scale sometimes insinuate themselves too thoroughly into questions connected with the duration of plant-types whether represented by families or genera4 ,we have been accustomed to regard ,cordaites as a genus confined to the ,palaeozoic period1 a type which with many others carried on the tradition of ,upper ,carboniferous forests to the ,permian floras and then made way for the precursors of ,mesozoic types4 ,there is1 however1 no valid reason for supposing that ,cordaites and other ,palaeozoic genera did not survive as less prominent members in succeeding floras4 ,it must be admitted that evidence in support of ,mesozoic ,cordaitales is not above suspicion1 though the probability is that ,cordaites or some allied genera still flourished in the earlier stages of the ,mesozoic era4 ,the data on which this opinion is based cannot be fully discussed in a general treatise1 but a few of the facts may be briefly considered4 ,zeiller#gbe and other authors have expressed the view that the ,cordaitales were not exclusively ,palaeozoic4 ,in addition to ,cordaites 7,noeggerathiopsis7 ,hislopi recorded from ,rhaetic floras1 other possible representatives of the group are illustrated by specimens included in such genera as ,yuccites1 ,bambusium and ,krammera4 ,pelourdea gen4 nov4 ,the name ,yuccites#gbf was given to some detached1 broad1 linear leaves from the ,bunter sandstone of the ,vosges which were compared with the foliage of ,yucca and classed among ,monocotyledons4 ,the authors of the genus also described a cylindrical cast as a ,yuccites stem1 including both stem and leaves in ,yuccites vogesiacus4 ,the supposed stem1 as ,fliche#gbg has shown1 is a pith-cast and is appropriately named by him ,endolepis vogesiacus4 ,the ,vosges leaves are assigned by this author to the genus ,cordaites1 a change of name which may eventually be justified though as yet based on insufficient evidence4 ,there are objections to the institution of a new name in place of ,yuccites1 but it is undesirable to retain a designation suggesting false ideas with regard to affinity4 ,a new name ,pelourdea 7after ,m4 ,pelourde of ,paris1 whose recent death deprives ,palaeobotany of an able and promising investigator7 is therefore proposed for leaves of the ,yuccites type which in form1 venation1 and spiral phyllotaxis agree with those of ,cordaites but cannot confidently be assigned to that genus or even to the ,cordaitales4 ,for linear leaves1 especially from ,jurassic strata1 resembling those of ,phoenicopsis the name ,desmiophyllum#gbh is employed3 these are very similar to those of ,pelourdea2 they are characterised by their fairly uniform breadth and afford no indication of their arrangement on the supporting axis4 ,pelourdea vogesiaca 7,schimper and ,mougeot74 ,the linear-lanceolate leaves described by ,schimper and ,mougeot as ,yuccites vogesiacus and transferred by ,fliche to ,cordaites are probably specifically identical with specimens described by ,mr ,wills#gbi from ,lower ,keuper rocks in ,worcestershire4 ,the ,english leaves were described by ,arber#gcj as ,zamites grandis1--the name ,zamites vogesiacus having been previously used by ,schimper and ,mougeot1--on the ground that the supposed leaves were probably pinnae of a cycadean frond1 a view in agreement with an opinion previously expressed with regard to similar leaves from ,stonesfield#gca4 ,a later discovery by ,wills of specimens1 on which the drawing reproduced in fig4 #dhd is based1 of the same type of leaf showing the foliar nature of the fossils necessitated the abandonment of the pinna-hypothesis1 and the original name ,yuccites vogesiacus was resuscitated#gcb4 ,the leaves reach a length of #ej cm4 and a maximum breadth of #fe cm42 the lamina is entire1 lanceolate or linear-lanceolate1 the apex acuminate1 and the lower part rather abruptly contracted and attached by a broad crescentic base2 veins numerous1 parallel1 and occasionally forked4 ,fliche records the occurrence of a small ,artisia-like pith-cast and pieces of stem with leaf-scars 7#d #c mm47 in association with leaves of ,pelourdea vogesiaca in ,triassic strata in ,lorraine4 ,an imperfectly preserved specimen described by ,fliche as ,cordaianthus ,minieri#gcc resembles an inflorescence of ,cordaites4 ,it consists of an axis #ae cm4 long1 the lower part forming a peduncle1 and on the upper portion are linear bracts subtending oblong bodies which may be lateral fertile shoots4 ,illustration3 ,fig4 #dhd4 ,pelourdea vogesiaca4 ,reconstruction of a foliage-shoot4 7,after ,wills47 ,pelourdea hadroclada 7,halle74 ,dr ,halle#gcd recently published an account of some imperfect leaves and stem-fragments from the ,rhaetic of ,scania which he named ,phyllotenia 787 hadroclada1 the generic name provisionally adopted having been proposed by ,salfeld#gce for some rather obscure remains from the ,corallian of ,germany4 ,it appears to have escaped the notice of both authors that ,saporta#gcf in #ahid had adopted the designation ,phyllotenia for some examples of broad parallel-veined leaves from ,lower ,cretaceous rocks in ,portugal very similar to ,velenovsk's ,krammera mirabilis#gcg4 ,some other generic name must therefore be used4 ,for the ,rhaetic species the name ,pelourdea would seem appropriate4 ,the type-specimen consists of an axis #aj-ab mm4 in diameter with spirally disposed transversely elongated leaf-scars bearing sessile linear leaves similar to ,poa-,cordaites2 none of them are complete1 the largest is #f cm4 long and #e-g mm4 broad with #h-ab parallel veins4 ,an examination of the original specimens in the ,stockholm ,museum satisfied me that ,dr ,halle is justified in the opinion that they may be fragments of some ,cordaitalean plant and that he was well advised to avoid the use of the name ,cordaites4 ,salfeld's species1 ,phyllotenia longifolia1 may be an imperfectly preserved example of ,phoenicopsis#gch1 but the material is too incomplete to be identified with any degree of confidence4 ,pelourdea ,imhofi 7,heer74 ,the ,triassic leaves from ,switzerland described by ,heer#gci1 and more recently by ,leuthardt#gdj1 as ,bambusium ,imhofi1 were referred by ,fliche#gda to the genus ,cordaites4 ,the lamina is ensiform1 #be cm4 long with a maximum breadth of #bd cm4 ,leuthardt's photograph of aerial stems and rhizomes of this supposed ,monocotyledon are far from convincing4 ,pelourdea keuperiana 7,compter74 ,the leaves from the ,lower ,keuper of ,thuringia assigned by ,compter#gdb to ,cordaites without adequate evidence resemble those of ,p4 vogesiaca1 but there is no evidence as to their manner of attachment2 they are #cj-dj cm4 long and from #ae to #b cm4 broad4 ,pelourdea megaphylla 7,phillips74 ,this species was first described by ,phillips#gdc from the ,middle ,jurassic ,stonesfield ,slate and afterwards referred to ,zamites#gdd3 the leaves bear a striking resemblance to foliage of the type ,cordaites borassifolius2 the lamina is #cj cm4 long and attains a breadth of #c cm41 the apex is acuminate and slightly contracted towards the broad concave base4 ,my former comparison of these ,stonesfield leaves with the long pinnae of ,ceratozamia mexicana seemed to be supported by ,phillips's type-specimen of ,palaeozamia longifolia4 ,it may be that the supposed pinnae in ,phillips's type are spirally disposed leaves3 if this is the case the specimen may be a fragment of a ,podozamites2 its specific identity with the larger detached specimens1 though probable1 cannot be demonstrated4 ,some leaves figured by ,zigno#gde from ,jurassic rocks of ,italy as ,yuccites ,schimperianus may be identical with ,p4 megaphylla4 ,pelourdea mirabilis 7,velenovsk ex ,corda ,,ms474 ,the generic name ,krammera1 suggested by ,corda1 was employed by ,velenovsk#gdf for large ,cordaites-like leaves from the ,lower ,cretaceous of ,bohemia1 for casts of cones regarded by him as stems1 and for fruit-like bodies4 ,the leaves1 previously described as ,flabellaria chamaeropifolia ,goepp41 ,dammara albens ,presl1 etc41 bear a close resemblance to the large broadly linear leaves of ,cordaites2 the lamina reaches a length of #dj cm4 and between the veins occur #a-d finer striations4 ,the fossils identified by ,velenovsk as stems bearing crowded imbricate scales1 which he regarded as the persistent bases of ,krammera leaves1 are probably cones2 they agree very closely in size and shape1 also in the form of the scales1 with cones of ,agathis and some other recent ,conifers4 ,as the designation ,krammera was instituted primarily for cones and not leaves the name ,pelourdea is substituted for it4 ,niponophyllum4 ,stopes and ,fujii4 ,niponophyllum cordaitiforme ,stopes and ,fujii4 ,the generic name ,niponophyllum#gdg was proposed for some petrified specimens of leaves or possibly leaflets from ,upper ,cretaceous beds in ,japan which1 though not definitely assigned to a group or family1 are considered by the authors of the genus #8to lie anatomically somewhere between ,cordaites and ,cycadeoidea' #8with a closer similarity to the former than to the latter if we compare the whole ,cordaites leaf with our blade4' ,the data on which this conclusion is based are1 however1 insufficient to justify a reference of ,niponophyllum to the ,cordaitales or indeed to lend any substantial support to the opinion that the ,japanese specimens are anatomically more akin to ,cordaites than to other plants4 ,the type-species is represented by two specimens of leaf-fragments about #jd mm4 thick and from #f to #i mm4 broad containing from #ba to #cc vascular bundles2 the upper part of the mesophyll is composed of palisade tissue and the stomata appear to be confined to the lower epidermis4 ,each bundle is accompanied by an ,i-shaped girder1 and small patches of sclerenchyma occur next the upper epidermis between the girders2 there are no resin-canals3 the vascular bundles are collateral1 the xylem is said to be almost entirely centripetal and exarch1 but in the absence of evidence afforded by longitudinal sections the details of structure cannot be definitely determined4 ,a comparison is made with ,cycadean leaves and with leaves of ,araucarineae and ,podocarpeae1 also with ,cordaites2 another type with which ,niponophyllum may be compared is ,desmiophyllum ,solmsi#gdh4 ,the genus is interesting as an example of a petrified gymnospermous type of leaf characterised by the absence of resin-ducts and transfusion-tracheids1 the possession of collateral1 apparently exarch1 bundles enclosed in a double sheath2 but the data supplied are insufficient to enable us to allocate the specimens to a position within the class4 ,a specimen described by ,schenk#gdi as ,eolirion primigenium from ,lower ,cretaceous beds in the ,carpathian mountains closely resembles in habit a foliage-shoot of ,poa-,cordaites2 the leaves are narrow and linear with obtuse apices and attached1 apparently1 in a close spiral4 ,schenk assigns the plant to the ,monocotyledons1 but its systematic position must be left unsettled4 99 99 99 99 99 ,the list of ,mesozoic specimens resembling ,cordaites leaves might be extended4 ,apart from some ,triassic and ,rhaetic examples which may well be ,cordaitalean1 there are many others which1 though similar in form and venation to ,cordaites1 are in all probability more closely related to ,agathis and other genera2 the species ,dammarites ,bayeri recently described by ,zeiller#gej from the ,upper ,cretaceous of ,bulgaria is a case in point4 ,the ,araucarian character of the wood of ,cordaites precludes any satisfactory discrimination between ,mesozoic ,araucarian stems and those of ,cordaitalean species1 at least in the case of such material as is usually available4 ,titanophyllum4 ,renault4 ,titanophyllum ,grand',euryi ,renault4 ,the remarkable leaves on which this genus and species are founded#gea were discovered in the ,commentry coalfield2 they occur as detached specimens and cannot be correlated with any known stem4 ,renault suggests that the ,autun stems referred to ,colpoxylon may have borne the ,titanophyllum leaves1 but this correlation rests only on the dimensions of the stems and the occurrence of transversely elongated scars on the surface4 ,the lamina is thick and coriaceous1 #gj-ge cm4 long and #bj-be cm4 in breadth2 the veins are parallel but not branched2 numerous longitudinal striations on the upper surface indicate the presence of hypodermal stereome-strands2 stomata are abundant on the lower surface and the more or less rectangular cells in the neighbourhood of the stomata appear to be papillose 7fig4 #dhe1 ,a1 ,b74 ,the distal region of the lamina is often torn into strips 7fig4 #dhe1 ,a72 the approximately rectangular leaf has a broad elliptical base #i-aj #c-d cm4 ,illustration3 ,fig4 #dhe4 ,titanophyllum ,grand',euryi4 ,a1 leaves nat4 size2 ,b1 stomata on the lower surface of the lamina4 7,after ,renault and ,zeiller47 ,dr ,white#geb describes a specimen from the ,lower ,coal ,measures of ,missouri as 8 ,titanophyllum ,brittsii which he speaks of as the thick base of a leaf similar to that described by ,renault but1 as ,white says1 no formal diagnosis is possible without more satisfactory material4 ,such evidence as is available suggests that ,titanophyllum is a type of ,cordaitalean leaf probably closely allied to ,cordaites4 ,,chapter ,,xxxiv4 ,,cordaitales4 ,c4 ,,pityeae4 ,pitys4 ,witham4 ,this generic name in the form ,pitus was first used by ,witham#gec for some petrified pieces of large stems from ,lower ,carboniferous strata in the south of ,scotland 7,berwickshire74 ,in an earlier paper ,witham#ged gives an account of the beds on the banks of the ,tweed from which the specimens of ,pitys and other plants were obtained4 ,the name was revived by ,goeppert#gee as a substitute for ,pissadendron#gef adopted by ,endlicher and ,unger3 ,scott#geg employed the older name in the account of his investigations1 which have added greatly to our knowledge of ,witham's types4 ,the distinguishing characters of ,pitys are3 the ,araucarian pitting of the secondary xylem1 the large pith1 the occurrence of numerous small primary xylem strands of mesarch structure in the peripheral region of the pith1 and the simple nature of the leaf-traces4 ,nothing is known of the extrastelar tissues1 and beyond the fact that the species were arborescent we have no information with regard to the foliar#geh or reproductive organs4 ,illustration3 ,fig4 #dhf4 ,pitys antiqua4 ,central region of stem1 showing primary xylem strands as black dots4 7,kidston ,collection1 #eih ,a47 ,pitys antiqua ,witham4 ,in #ahii ,scott#gei published a preliminary description of some sections in the possession of ,dr ,kidston from ,lennel ,braes 7,berwickshire3 ,calciferous series7 under the name ,araucarioxylon antiquum1 but in the more complete account the name ,pitys#gfj is adopted4 ,the following description is based on ,scott's paper and on the examination of the sections4 ,fig4 #dhf represents a diagrammatic sketch of a section 7#bg #bg cm47 of the central region of a stem which had lost most of its secondary wood4 ,in some cases the pith reaches a diameter of #c cm42 it consists of large parenchymatous cells broader than deep1 several of which contain a black substance and are probably secretory elements3 the intercellular spaces are fairly large4 ,horizontally extended gaps1 due to shrinkage and collapse1 occur in the pith and give to it an appearance not unlike that of ,cordaites4 ,numerous small elliptical strands of primary xylem1 #jae-jc mm4 in diameter1 are scattered in the peripheral region 7fig4 #dhf7 at varying distances from the inner edge of the secondary wood and occasionally1 when about to bend outwards as a leaf-trace1 a primary xylem-strand abuts directly on the secondary xylem4 ,the protoxylem occupies a more or less central position in each mesarch strand 7fig4 #dhg1 ,b1 px73 the centrifugal tracheids have the ,araucarian pitting while the centripetal elements are spiral4 ,a few parenchymatous cells are associated with the more central tracheids4 ,a leaf-trace about to bend outwards into the zone of secondary wood is double1 but at a slightly higher level in its course it assumes the form of a single strand4 ,the foliar bundles are thus single and not true double traces4 ,scott recognised1 at the extreme edge of the pith1 an association with outgoing leaf-traces of a single reparatory strand deeper in the medullary tissue4 ,in this species there is no evidence that an outgoing trace is accompanied by an arc of secondary xylem1 but that such was the case is rendered highly probable by the discovery of an arc of wood added by the cambium to a leaf-trace in ,pitys ,withami#gfa4 ,the radial disposition of the pith-cells1 many of which appear to be secretory1 around each primary xylem-strand 7fig4 #dhg1 ,b7 is a characteristic feature4 ,a difficult problem1 namely the relation of primary xylem and phloem1 is raised by the fact that the primary strands are composed exclusively of xylem and are in most cases separated from the secondary wood by several parenchymatous cells4 ,scott favours the view that the primary phloem was originally at some distance from the primary xylem1 the cambium being formed nearer to the phloem1 an arrangement foreign to recent ,gymnosperms4 ,it is perhaps conceivable that the primary conducting strands included no true phloem4 ,illustration3 ,fig4 #dhg4 ,pitys antiqua4 ,a1 radial section of secondary xylem2 ,b1 transverse section showing the inner edge of the secondary wood and two primary-xylem strands with protoxylem1 px4 7,kidston ,coll47 ,the secondary xylem consists of tracheids with #d-e alternate rows of hexagonal pits on the radial walls 7fig4 #dhg1 ,a7 and not infrequently on the tangential faces4 ,near the ends of the tracheids the pits are occasionally more scattered and separate and may be reduced to a single row#gfb1 but on the whole the pitting is essentially ,araucarian4 ,the medullary rays are generally #d cells in breadth1 but may be #g cells broad4 ,in depth the rays extend to #gj cells4 ,as seen in fig4 #dhg1 ,b1 the inner ends of the rays are especially broad owing to the tangential dilatation of the cells4 ,the innermost secondary tracheids are characterised by pitting intermediate between spiral and reticulate4 ,there are no regular rings of growth in the wood4 ,pitys primaeva ,witham4 ,this species#gfc1 also founded on material from the ,calciferous sandstone of ,berwickshire1 differs from ,p4 antiqua in the broader and shorter form and greater breadth of the medullary rays 7fig4 #dhh1 ,a1 ,b71 also in the larger tracheids and in the less crowded arrangement of the bordered pits in which the circular form sometimes replaces the hexagonal type4 ,the structure of the pith is not known1 but ,scott was able to recognise in the partially preserved pith of a branch indications of primary-xylem groups and other features pointing to a close resemblance to ,p4 antiqua#gfd4 ,a piece of stem originally described by ,williamson#gfe as ,lyginodendron 787 anomalum from the ,lower ,carboniferous volcanic ash of the ,isle of ,arran would appear to be closely related to1 if not specifically identical with1 ,p4 primaeva and1 as ,scott says1 it should at least be included in the same genus4 ,illustration3 ,fig4 #dhh4 ,pitys primaeva4 ,a1 transverse section of the secondary xylem2 ,b1 tangential section of the secondary xylem4 7,from sections of the type-specimen in the ,edinburgh ,university ,botanical ,department47 ,pitys ,withami 7,lindley and ,hutton74 ,the ,craigleith ,tree4 #ahca4 ,pinites ,withami ,lindley and ,hutton1 ,foss4 ,flora1 ,vol4 i4 ,pl4 ii4 #ahca4 ,pinites medullaris1 ,ibid4 ,pl4 iii4 #aijb4 ,pitys ,withami ,scott1 ,trans4 ,r4 ,soc4 ,edinb4 ,vol4 xl4 p4 #ced1 ,pl4 ii4 fig4 #aj3 ,pl4 vi4 fig4 #ba4 ,this species was founded on some sections cut from an incomplete stem #cf feet long obtained in #ahbf from the ,calciferous sandstone of the ,craigleith quarry near ,edinburgh4 ,the specimen named by ,lindley and ,hutton ,pinites medullaris is no doubt specifically identical with the larger stem4 ,in the same year 7#ahca7 ,witham#gff published an account of a still larger stem from the same locality1 #dg ft long and #e ft in diameter in the lower part1 and in his book the name ,pinites ,withami is adopted4 ,a large specimen of this tree is erected in the grounds of the ,natural ,history ,museum1 ,london1 and other specimens are preserved in the ,edinburgh ,botanic ,garden4 ,goeppert in #ahej referred the species to ,dadoxylon and later to ,pitys#gfg1 while ,brongniart#gfh assigned it to his genus ,palaeoxylon4 ,scott#gfi1 who examined ,witham's sections placed it in ,pitys4 ,the pitting of the secondary tracheids is often multiseriate1 but the medullary rays are narrower than in ,pitys antiqua and ,p4 primaeva1 rarely exceeding #d cells in breadth1 though still of the manoxylic type4 ,primary-xylem strands occur in the peripheral region of the pith agreeing closely with those of ,p4 antiqua4 ,there are no regular and continuous annual rings though as ,witham stated there are concentric markings on the wood which superficially resemble true rings4 ,the leaf-traces are single and in their passage through the cylinder of wood an arc of secondary tracheids is added to the primary elements4 ,archaeopitys4 ,scott and ,jeffrey4 ,archaeopitys ,eastmanii ,scott and ,jeffrey4 ,the genus ,archaeopitys#ggj has recently been instituted for a specimen of a stem from the ,lower ,carboniferous rocks of ,kentucky which differs from ,pitys antiqua1 the type with which it is most closely allied1 in the position and behaviour of the primary vascular strands in the pith4 ,the type-specimen is a piece of stem #bg cm4 in diameter including a solid parenchymatous pith #ee mm4 broad and a cylinder of secondary wood4 ,the wood is similar to that of ,cordaites2 the tracheids have #b-c rows of pits but for the most part the details of structure are not preserved2 the medullary rays are both uniseriate and multiseriate and not very deep2 the structure is more ,cordaitean than ,cycadean4 ,a characteristic feature is the occurrence of about #cj vascular bundles in the medullary region3 these mesarch strands1 with the protoxylem near the centre1 are scattered through the pith and several lie on the outer edge in contact with the secondary xylem or are partially embedded in the xylem-cylinder4 ,the examination of a series of sections demonstrated the fusion of perimedullary with medullary strands and the occasional union of the strands of both regions with one another4 ,it appears that the perimedullary strands are the leaf-traces while the strands deeper in the pith are merely branches from the peripheral leaf-trace strands4 ,in ,pitys antiqua the medullary xylem strands are confined to the outer zone of the pith and constitute the leaf-traces3 in ,archaeopitys1 on the other hand1 the medullary strands are scattered through the pith and the leaf-traces are restricted to the circummedullary region in actual contact with the secondary xylem4 ,in the ,devonian genus ,callixylon there are similar strands but they are confined to the edge of the pith and are usually in contact with the wood as are the circummedullary strands in ,archaeopitys4 ,the grouping of the secondary xylem of ,callixylon into wedge-shaped masses at the inner edge of the cylinder is a characteristic feature2 this feature is less definite in ,archaeopitys and absent from ,pitys4 ,callixylon4 ,zalessky4 ,callixylon ,trifilievi ,zalessky4 ,this genus is represented by a single species#gga1 originally referred to ,dadoxylon1 founded on material from ,upper ,devonian rocks in the ,donetz basin1 ,russia1 and based solely on the anatomical characters of the secondary wood and central region of an arborescent stem4 ,the wood is pycnoxylic and of the ,araucarian type2 the inner portion of the xylem-cylinder is divided into groups1 similar to the regular wedges in a ,calamite stem1 consisting of tracheids converging towards an obtuse apex occupied by a primary xylem strand1 fig4 #dhi1 ,a1 a1 b4 ,on the radial walls of the tracheids the bordered pits not infrequently form a single row of flattened ovals1 but more usually there are two or sometimes three rows of alternate contiguous pits 7fig4 #dhi1 ,b73 circular and separate pits also occur4 ,as ,zalessky states1 the pits do not always occupy the whole radial face2 unpitted patches sometimes interrupt the continuity of the pitted areas#ggb4 ,similar circular and more scattered pits are unusually abundant on the tangential walls4 ,there are no complete rings of growth4 ,the medullary rays are narrow and1 except at their dilated inner ends1 uniseriate2 usually one or a few cells deep1 they may reach a depth of #ab or more cells4 ,the pits on the radial walls of the ray-cells are said to be #d-g in the field4 ,the pith consists of thin-walled flattened parenchyma frequently elongated in a radial direction4 ,at the inner edge of the secondary xylem and generally in contact with it are several anastomosing strands of primary xylem1 mesarch in structure but with the protoxylem nearer the inner edge4 ,these bundles may be single 7fig4 #dhi1 ,a1 a7 or double 7fig4 #dhi1 ,a1 b1 and ,c7 and closely resemble those of ,pitys antiqua except in their closer relation to the secondary wood4 ,the leaf-traces have not been described1 but the occurrence of twin-bundles like those in fig4 #dhi1 ,c1 suggests that they were double4 ,the primary-xylem elements show particularly well transitional forms of pitting connecting the multiseriate and scalariform types4 ,callixylon1 though conveniently and justly regarded as a distinct genus1 exhibits in its primary xylem a fairly close agreement with ,pitys#ggc4 ,the above account is based in part on ,zalessky's description and partly on specimens in ,dr ,kidston's possession4 ,illustration3 ,fig4 #dhi4 ,callixylon ,trifilievi4 ,a1 ,c1 the inner margin of the secondary xylem showing strands of primary xylem1 a1 b1 and ,c4 ,b1 tracheids of the secondary xylem4 7,a1 ,c1 from photographs supplied by ,prof4 ,zalessky2 ,b1 ,cambridge ,botany ,school47 ,miss ,elkins and ,w4 ,wieland#ggd have recently described some ,upper ,devonian wood from ,indiana characterised by a grouping of the circular or elliptical bordered pits in the radial walls of the tracheids similar to those in ,callixylon ,trifilievi which they include together with the ,middle ,devonian species ,cordaites ,newberryi#gge in ,zalessky's genus4 ,though these two ,american species are comparable in the discontinuous arrangement of the tracheal pits with the ,russian type the latter is characterised by the presence of primary xylem-strands1 a feature that has not been recognised in the ,american stems3 it would seem1 then1 undesirable to adopt the designation ,callixylon in preference to ,dadoxylon unless there is evidence as to similar characters in the primary region of the xylem4 ,coenoxylon4 ,zalessky4 ,coenoxylon ,scotti ,zalessky4 ,prof4 ,zalessky#ggf gave the name ,coenoxylon to a small and incomplete piece of stem of doubtful provenance but possibly from the ,ural ,permian beds4 ,the pith1 #b cm4 broad1 consists of parenchyma associated in the central region with numerous large sclerous cells4 ,in one section a sinuous band of meristematic tissue was observed near the periphery of the pith3 the appearance of this tissue in a photograph given to me by ,prof4 ,zalessky suggests comparison with occasional strips of similar dividing cells in the pith of ,lyginopteris4 ,the secondary wood is composed of tracheids with #a-b rows of flattened or hexagonal pits on the radial walls and narrow uniseriate medullary rays reaching a depth of #ae cells and with #b-g oval pits in the field4 ,as in the wood of ,mesopitys ,tchihatcheffi#ggg there are distinct and apparently complete rings of growth4 ,it is on the ground of the arrangement and structure of the primary xylem that ,zalessky instituted a new generic name4 ,the primary xylem forms teeth of variable size which project into the pith from the edge of the secondary xylem3 the prominent portions of the main mass of primary xylem give off branches1 differing considerably in size and shape1 some of which become separated by a comparatively broad band of parenchyma from the parent xylem-tissue4 ,these bundles anastomose in their course through the pith and in doing so incorporate between them patches of parenchyma4 ,the bundles of primary xylem are endarch4 ,from the centrifugal strands at the periphery of the pith double leaf-traces are produced which pass almost horizontally through the secondary wood4 ,as ,zalessky points out1 the leaf-traces in their dual nature and in the elongated and narrow form of the tracheal groups1 as seen in tangential section of the secondary wood1 bear a close resemblance to those of ,ginkgo biloba4 ,this ,russian genus agrees in its double leaf-trace with ,mesoxylon1 ,mesopitys1 and ,antarcticoxylon3 among recent plants ,ginkgo would seem to be the most closely allied type4 ,parapitys4 ,zalessky4 ,the designation ,parapitys#ggh has been proposed for a single ,upper ,carboniferous species characterised by the possession of secondary wood like that of ,cordaites1 double leaf-traces1 and small mesarch primary xylem-strands4 ,nothing is known of the leaves or reproductive organs4 ,parapitys ,spenceri 7,scott74 ,in #ahhj ,williamson#ggi published a short account of a transverse section of a specimen found by ,mr ,j4 ,spencer in ,upper ,carboniferous strata near ,halifax in ,yorkshire which afforded evidence of the occurrence of double leaf-traces4 ,the following description is taken from ,scott's account#ghj of the species1 which he named ,dadoxylon ,spenceri4 ,the parenchymatous pith1 #e-f mm4 in diameter1 is obtusely pentagonal1 the prominent angles corresponding to the points of exit of paired leaf-traces like those of ,mesoxylon1 ,ginkgo1 and other genera4 ,the secondary xylem consists of narrow tracheids with crowded multiseriate pits on the radial walls and narrow medullary rays one-cell broad and #a-h cells deep4 ,in contact with the inner margin of the secondary wood are a few small mesarch strands of primary xylem1 the protoxylem and some parenchyma occupying a more or less central position4 ,a leaf-trace about to enter the secondary xylem is represented by twin-bundles which retain their double nature as they traverse the stele1 but at a lower level the two components fuse and appear as single bundles at the outer edge of the pith4 ,the division of a leaf-trace into two before passing out1 as in ,poroxylon1 constitutes a difference from ,lyginopteris in which the division occurs later4 ,zalessky's generic name ,parapitys is an appropriate substitute for ,dadoxylon in view of the presence of separate primary xylem strands1 a feature foreign to typical ,dadoxylons which agree with recent ,conifers and ,cycads in the absence of vascular strands distinct from the endarch centrifugal wood4 ,as ,scott#gha says1 ,parapitys #8is best regarded as a near ally of ,mesoxylon4' ,mesopitys4 ,zalessky4 ,mesopitys ,tchihatcheffi 7,goeppert74 ,the genus ,mesopitys was instituted by ,zalessky for a ,permian species founded by ,goeppert#ghb on a piece of decorticated stem from the ,kousnetzk basin in ,siberia and afterwards more fully described by ,goeppert and ,stenzel#ghc4 ,the structure of the secondary wood led ,goeppert to adopt the name ,araucarites for which ,kraus#ghd substituted ,araucarioxylon4 ,a recent investigation of additional material by ,zalessky brought to light the existence of groups of primary xylem abutting on the secondary xylem and projecting into the pith1 characterised by the occurrence of spiral protoxylem elements on the inner edge4 ,the recognition of this important feature justified ,zalessky in the adoption of a new generic term4 ,in general anatomical characters ,mesopitys agrees with ,eristophyton ,beinertianum 7,goepp47 but is distinguished by the more feebly developed primary-xylem groups and by their endarch structure4 ,the examination of sections from some of ,prof4 ,zalessky's material lent to me by ,dr ,kidston enables me to confirm ,zalessky's description1 though ,i am not convinced that the primary xylem-strands are exclusively endarch3 in most of the primary groups the protoxylem is clearly on the inner edge1 but in a few cases there may be a small amount of centripetal xylem present4 ,the characters of ,mesopitys ,tchihatcheffi may be summarised as follows3 ,annual rings well defined1 varying considerably in breadth2 the summer wood is represented by several rows of narrower tracheids 7fig4 #dij1 ,a74 ,in the piece of stem shown in the figure the breadth of the wood from the flattened and crushed pith to the broken outer edge is #f cm4 ,the medullary rays are numerous1 uniseriate1 rarely #b cells in breadth2 the pits on the radial walls of the ray-cells1 #g-aj in the field1 are apparently simple1 oval1 and oblique3 the rays are generally #c-d cells in depth but may be deeper4 ,there are #a-c rows of hexagonal alternate rows of pits on the radial walls of the tracheids4 ,the primary xylem consists of groups1 varying in size and sometimes reduced to a very few elements1 in contact with the secondary xylem1 usually though probably not invariably endarch4 ,in the two narrow radially elongated and partially destroyed primary strands shown in fig4 #dij1 ,b1 the protoxylem1 px1 is on the inner edge4 ,the leaf-trace passes through the secondary wood as a single strand4 ,in the section reproduced in fig4 #dij1 ,a1 the crushed and flattened pith measures #i by #b mm42 it consists of thin-walled parenchyma with a few scattered thicker-walled cells4 ,illustration3 ,fig4 #dij4 ,mesopitys ,tchihatcheffi4 ,a1 transverse section showing rings of growth in the wood4 ,b1 primary xylem with protoxylem1 px1 and the edge of the secondary xylem1 x4 7,kidston collection1 #baef47 ,nothing is known as to the structure of the cortical tissue or leaves4 ,antarcticoxylon4 ,seward4 ,antarcticoxylon ,priestleyi ,seward4 ,the specimen on which this genus was founded was discovered by ,mr ,raymond ,priestley#ghe in a boulder1 probably derived from the ,upper ,beacon sandstone1 on the ,priestley ,glacier south of #gd ,s4 lat4 in the course of the journey of the ,northern ,party of ,capt4 ,scott's second ,antarctic ,expedition4 ,the type-specimen is a piece of silicified stem #a ft long and #c ins4 in diameter2 there were no tissues preserved external to the secondary wood and it is impossible to say what proportion of the original thickness is represented4 ,annual rings are clearly marked at least macroscopically 7fig4 #dia1 ,c7 though there is very little difference between the spring and summer tracheids3 the centre of the compressed stem is occupied by a lighter coloured elliptical area #g #b mm4 which superficially resembles a pith1 but in the peripheral region it consists of portions of a cylinder of spiral and scalariform tracheids1 the actual pith being not more than #b-c mm4 in breadth4 ,the pith consists of lacunar parenchyma separated by horizontal bands of dark cells containing some secreted substance 7fig4 #dia1 ,f73 the preservation is1 however1 not sufficiently good to enable one to describe it in detail4 ,the secondary xylem is of the pycnoxylic type2 the tracheids have either a single row of contiguous and partially flattened pits on their radial walls or a double row of alternate polygonal pits2 the medullary rays are nearly always uniseriate 7fig4 #dia1 ,e7 and from #a to #bd cells in depth4 ,at the inner edge of the secondary wood there was a fairly broad zone of more delicate tracheids 7fig4 #dia1 ,a1 x7 characterised by spiral or scalariform bands and by their relatively small diameter4 ,this innermost zone1 which supplies the leaf-traces1 is spoken of as the primary xylem2 it appears to be endarch though this cannot be definitely determined4 ,a characteristic feature of the primary xylem in the perimedullary region1 as also in the leaf-traces on their way through the secondary wood1 is the presence of short and broad tracheids 7fig4 #dia1 ,d1 t7 with reticulate thickening bands3 these short elements may represent centripetal xylem and are similar to the short tracheids described by ,scott#ghf in the sheath of ,mesoxylon ,lomaxi and to the larger elements in the stem of ,megaloxylon#ghg4 ,an interesting feature seen in transverse sections of the secondary wood is the occurrence of light bands concentric with the rings of growth which are broadest near the long axis of the stem 7fig4 #dia1 ,c74 ,in their narrower parts these bands are clearly due to the partial destruction of the secondary tracheids1 but in other places crushed parenchymatous tissue occurs which may be a traumatic phenomenon or possibly comparable with ,nrdlinger's #8medullary spots#ghh' formed by local hypertrophy of medullary tissue4 ,although the structure of the leaf-traces cannot be definitely determined1 it would seem that each trace passed into the perimedullary region as a single bundle of relatively large size composed of spiral and scalariform tracheids narrower than the secondary elements4 ,the traces during their outward course were accompanied by some parenchymatous tissue continuous with that in the pith1 and the inner spiral tracheids of the trace were connected with isodiametric reticulate elements4 ,the dimensions of the leaf-traces point to leaves of fairly large size4 ,illustration3 ,fig4 #dia4 ,a-,f1 ,antarcticoxylon ,priestleyi4 ,a1 ,b1 transverse sections of the xylem2 a1 small tracheids simulating protoxylem2 x1 xylem at the edge of the pith4 ,c1 transverse section showing leaf-traces1 l1 a1 b4 ,d1 leaf-trace with short tracheids1 t1 in the pith2 s1 sclerous cells4 ,e1 tangential section4 ,f1 pith in longitudinal section4 ,g1 ,pityosporites antarcticus2 see ,vol4 iv4 7,all the sections are in the ,british ,museum47 ,in the structure of the secondary wood ,antarcticoxylon agrees on the whole with an ,araucarian stem3 the broad zone of xylem composed of spiral and scalariform tracheids at the edge of the pith is a feature common to ,mesoxylon1 ,cordaites1 and ,araucaria4 ,there is no evidence of the occurrence of double leaf-traces such as characterise certain ,cordaitalean genera and some existing members of the ,araucarineae4 ,in the single nature of the leaf-traces the ,antarctic stem resembles ,mesopitys ,tchihatcheffi also in the presence of rings of growth#ghi1 but in ,antarcticoxylon the preservation of the primary xylem is too imperfect to admit of any satisfactory comparison as regards this important tissue with other types4 ,the precise age of the ,beacon sandstone has not been determined1 but the probability is that the upper beds from which the boulder containing ,antarcticoxylon was derived are not older than the ,rhaetic period4 ,the chief interest of this imperfectly preserved stem with undoubted ,araucarian affinities is its occurrence in the rocks of ,antarctica in association with other remains of comparatively large stems4 ,,chapter ,,xxxv4 ,,palaeozoic ,,gymnospermous ,,seeds4 ,seeds are abundantly represented as fossils from ,carboniferous to ,post-,tertiary deposits4 ,the importance of fossil and sub-fossil species in the later geological series has been demonstrated by the investigations of ,mr and ,mrs ,clement ,reid and a few other workers in this neglected field4 ,in cases where it is possible to assign seeds to their parent-plants the descriptions of casts1 impressions1 or petrifactions are added to the account of vegetative organs2 but it frequently happens that seeds are preserved only as detached specimens many of which have little or no value as botanical records1 while others that afford striking examples of the possibilities of petrifaction as a means of preserving the most delicate structures1 are of great importance4 ,in ,volume ii4 an account was given of such ,palaeozoic seed-bearing organs as ,lepidocarpon and ,miadesmia1 and the genera ,lagenostoma1 ,sphaerostoma1 and ,trigonocarpus are dealt with in this volume under ,lyginopteris1 ,heterangium1 and ,medullosa4 ,certain seeds afford some evidence as to the systematic position of the parent-plants though insufficient to warrant more than a surmise as to the nature of the vegetative organs3 in several cases it is only from the resemblance of detached seeds to types that on the strength of more or less convincing evidence are referred to definite parent-plants that any conclusions can be drawn with regard to precise systematic position4 ,in view of the occurrence of several different types of seeds that retain their morphological features1 but cannot be assigned with any degree of certainty to genera founded on vegetative organs1 a special chapter is devoted to a comparative study of selected examples with the object of directing attention to data bearing on evolutionary problems4 ,the chief interest of ,palaeozoic seeds to the botanist lies in the facts they contribute towards the elucidation of questions connected with the promotion of the megasporangium and megaspore of the ,pteridophyta to the higher stage represented by the integumented megasporangium 7nucellus7 and single megaspore that in the main fulfil the definition of a seed#gij4 #8,with the evolution of the seed1' as ,oliver says1 #8the plant rose at a bound to a higher plane1 and this structure in its perfected form has become the very centre of the plant's existence#gia4' ,we can as yet form a very partial conception of the successive stages in the adoption of the seed-habit1 but since #ahee1 the year in which ,hooker and ,binney#gib published their paper on the structure of ,trigonocarpus1 ample proof has been furnished of the importance of ,palaeozoic seeds from the standpoint of affinity between recent ,gymnosperms and extinct seed-bearing plants1 and of the modus operandi of evolutionary tendencies4 ,a cursory examination of ,palaeozoic seeds suffices to demonstrate their resemblance to those of recent ,cycads and the seed of ,ginkgo biloba2 but while it is clearly with these ,gymnosperms that the majority of the seeds described in the following pages are most closely allied1 the extinct types possess many distinguishing features that throw light on some at least of the factors concerned in the production of the modern type4 ,in many of the ,palaeozoic seeds the nucellus stands free within the integument1 to which it is attached only in the chalazal region1 in contrast to the lateral union between integument and nucellus in the ovules of recent ,cycads4 ,it has been suggested by ,oliver#gic that the seed of the ,conifer ,torreya affords a clue to the interpretation of this difference and that the lower part of the seed in ,cycads and ,torreya represents a later intercalation in the basal portion of the ovule1 the ancient type having a free nucellus in contrast to the nucellus of modern seeds which is free only at the apex4 ,it has been objected#gid that there are no adequate grounds for assuming the addition of an intercalated zone or of the elongation of the ovule that this implies1 the more probable view being that the lateral union of nucellus and integument represents congenital fusion in the ancestral type1 a fusion comparable with that of the coherent petals of a gamopetalous corolla4 ,in the presence of a pollen-chamber most of the ,palaeozoic seeds agree with those of recent ,cycads1 but in the extinct forms it is usually a more highly developed structure4 ,the name pollen-chamber was given by ,brongniart#gie to the pollen-containing cavity in the free region of the nucellus in the petrified seeds from ,st tienne in ignorance of the use of the same term by ,griffith#gif in a posthumous work published in #aheb for the nucellar chamber in ,cycas#gig4 ,the genus ,stephanospermum 7fig4 #did1 ,a7 illustrates the means by which the pollen-chamber was liberally supplied with water and thus adapted to the requirements of fertilisation by motile gametes4 ,the pollen-chamber and its vascular supply paved the way for siphonogamy1 that is the development of a pollen-tube for the more direct transmission of the male sperms4 ,the highly developed mantle of tracheal tissue at the periphery of the nucellus in ,stephanospermum1 represented on a reduced scale by the separate vascular strands of other seeds1 may be compared with the tracheal investment to the nucellus in the recent ,dicotyledonous genus ,cassytha#gih4 ,the presence of a nucellar vascular system in several ,palaeozoic seeds is a feature in which they differ from those of recent ,cycads with the exception of ,bowenia4 ,the retreat of the vascular supply from the immediate neighbourhood of the pollen-chamber in recent ,cycads may1 as ,oliver points out1 be correlated with the evolution of the pollen-tube--the substitution of siphonogamy for zoidiogamy4 ,the diagram reproduced in fig4 #dib represents a synthetic type based on such seeds as ,stephanospermum and ,cardiocarpus which illustrate an arrangement of conducting tissue frequently found in ,palaeozoic seeds3 the main strand gives off a pair of bundles in the sarcotesta in the principal plane1 as in ,cardiocarpus#gii2 from the tracheal mass in the chalazal region numerous bundles pass up the nucellus as far as the floor of the pollen-chamber4 ,the nature of the vascular supply in this generalised type and in individual genera should be compared with that in the seeds of recent ,cycads#hjj described in ,chapter xxviii4 ,illustration3 ,fig4 #dib4 #8,a conjectural synthetic type of seed embodying the characters of such a seed as ,stephanospermum with those of a ,cardiocarpus'2 n1 nucellus2 pc1 pollen-chamber4 7,after ,oliver47 ,recent research has revealed the not unexpected fact that in such ,upper ,carboniferous petrified seeds as have been investigated--a small proportion of the large number produced in the ,palaeozoic forests--there was a remarkable range in the mechanism connected with pollination and the maturation of the microspores4 ,a comparison of the genera ,physostoma1 ,lagenostoma1 ,conostoma1 ,trigonocarpus1 ,stephanospermum and others reveals the occurrence of very different though not unrelated structural features especially in the apical region of the seed4 ,these seeds1 including ,physostoma1 probably the most archaic type1 represent a stage in evolution already far removed from the starting-point3 the diversity of plan recalls the variety in the form of the chloroplasts in the ,green ,algae1 and in both cases we are in touch with an experimental phase representing a tentative advance towards greater efficiency4 ,in its differentiation into an outer fleshy region1 the sarcotesta1 a stony layer1 the sclerotesta1 and in many cases an inner flesh1 the ,palaeozoic seeds resemble recent ,cycads3 in both extinct and modern seeds the balance of evidence would seem to be in favour of attributing a single rather than a double origin to the integument4 ,among the numerous types of ,palaeozoic seeds are several which invite comparison with the fruits or carpels1 apart from the seeds1 of ,angiosperms4 ,impressions of ,samaropsis seeds 7figs4 #ejb1 ,b-,k2 #ejc2 #ejd7 bear a close resemblance to the laterally expanded fruits of the common ,crucifer ,thlaspi arvense2 the ribbed testa of ,hexagonocarpus 7fig4 #ejf1 ,h7 and other genera recalls the fruit-wall of ,alstroemeria2 the recently described ,lower ,carboniferous seed ,thysanotesta sagittula ,nath4 7fig4 #ejf1 ,f7 simulates a carpel of ,erodium4 ,these and similar instances of a close parallelism in external features between organs that are not homologous1 though in themselves of no morphological significance1 are at least interesting as illustrating the plasticity displayed by reproductive structures1 which in the ,palaeozoic period marked a morphological achievement comparable in its importance with the still greater achievement represented by the highly specialised fruits of the modern ,flowering plants4 ,the range in form and surface-features of ,angiospermous fruits was foreshadowed by ,palaeozoic seeds4 ,structural types and in some cases1 superadded to these1 features which may reasonably be supposed to have facilitated dispersal had been acquired by the seeds of ,palaeozoic plants in forms that in a much later period were adopted by fruits even to a greater degree than by seeds4 ,characters useful in seed-dispersal1 that are now shared by fruits and seeds1 are illustrated by the fleshy and possibly edible seeds of extinct ,gymnosperms1 the plumes and hairy beak of ,gnetopsis 7fig4 #did1 ,e7 and ,thysanotesta 7fig4 #ejf1 ,f7 suggestive of feathery stigmas and other appendages4 ,the lacunar sarcotesta of ,aetheotesta1 the thick endotesta of ,pachytesta 7fig4 #dig71 and the air-chamber of ,codonospermum 7fig4 #dih71 are strictly comparable with aids to buoyancy in fruits of existing ,flowering plants4 ,the mucilage-hairs and superficial cells in ,physostoma 7fig4 #did1 ,i7 and ,stephanospermum may be compared with the thick mucilaginous investment of the megaspores of recent water-ferns and with similar tissues of some ,angiospermous seeds4 ,the bionomics of ,palaeozoic plants is a subject worthy of more serious attention than it has so far received4 ,the search for morphological characters that may have facilitated the wanderings of widely distributed genera and species and a closer investigation of physiological-anatomical problems presented by the vegetative organs of petrified plants would not only extend our knowledge of the morphology of ancient types but would stimulate comparative study and1 incidentally1 relieve the dullness of pure description4 ,it may be argued that we should first establish a more solid foundation by further observations on living plants2 but even at the risk of allowing speculation too free a hand the attempt is worth making1 and it may be urged that1 as in phylogenetic enquiries so in other branches of botany1 facts obtained from plants of other ages may serve to supply deficiencies in knowledge based only on existing forms4 ,one of the difficulties inseparable from the study of fossil plants1 namely the identification of impressions and casts with specimens exhibiting anatomical characters1 is particularly well illustrated by seeds4 ,the description of a genus based on mere external form may sometimes be extended without great risk of error to include species founded on anatomical characters1 but on the other hand1 there are many instances in which--despite a general resemblance in form and size between petrifactions and impressions--lack of evidence of generic identity requires the employment of distinctive names4 ,the determination of impressions is1 as ,lesquereux recognised1 #8subject to a great deal of uncertainty1' and many of the genera founded on external features are purely artificial and include species that have no essential features in common4 ,moreover in the case of petrified specimens the apparent absence of an external fleshy layer is often due to destruction before preservation3 as ,solms-,laubach#hja points out1 it is obviously impossible to be certain as to the number of integumental layers in seeds that are not well preserved in all their parts4 ,goeppert founded a new genus1 ,acanthocarpus1 on a ,permian seed described as ,a4 xanthioides#hjb1 because of the occurrence of spinous processes attached to an obcordate kernel3 these apparent spines are in all probability the remains of a very imperfectly preserved sarcotesta4 ,the preservation of the central portion of a seed1 that is the seed-cavity with the enclosing shell1 conveniently called the nucule1 has often led to an unnecessary multiplication of generic terms4 ,other examples of confusion resulting from different states of preservation are quoted in the accounts of some of the selected types4 ,williamson in #ahgg pointed out that we learn from the large number of different kinds of ,palaeozoic seeds that #8there were in the ,carboniferous forests many gymnospermous stems clothed with foliage of which we have not yet discovered any traces1 probably because these ,gymnosperms did not flourish upon the low swampy grounds which were the homes of the great mass of the coal-producing plants#hjc4' ,prof4 ,zeiller#hjd has also drawn attention to the numerical excess of seeds over vegetative organs4 ,this discrepancy has to a large extent been explained by the discovery that many of the supposed ,ferns were seed-bearing plants1 and a further explanation is suggested by the superiority of seeds over stems and leaves in their adaptation to dispersal by water4 ,in #ahgd ,brongniart#hje described several petrified seeds from material discovered by ,grand',eury in the ,st tienne coal-field1 and seven years later his descriptions were republished#hjf1 with the addition of several beautifully executed drawings1 as a posthumous volume edited by his distinguished pupil ,renault4 ,williamson's researches supplied much additional information1 and in recent years the more detailed study of ,french and ,english seeds by ,bertrand and particularly by ,oliver and his pupils has further emphasised the interest and importance of this field of work4 ,brongniart proposed a two-fold classification of ,french seeds3 7i7 bilaterally symmetrical seeds1 more or less flattened in section1 which he believed to be ,cordaitean2 7ii7 radially symmetrical seeds1 circular in transverse section3 the latter group he considered to be less closely allied to recent types4 ,the employment of the terms ,platyspermeae and ,radiospermeae1 proposed by ,oliver#hjg for ,brongniart's divisions1 serves a useful purpose if due regard is paid to the adequacy of the evidence as to symmetry and if it is recognised that this classification cannot be rigidly employed in all cases4 ,it was pointed out by ,brongniart that the occasional occurrence of tricarinate seeds of ,ginkgo 7fig4 #fca7 and ,taxus is an exception to the general rule of bilateral symmetry3 seeds of ,cycas are normally bilateral1 but radially symmetrical forms also occur#hjh4 ,the genus ,conostoma 7fig4 #did1 ,b7 represents an intermediate type which1 though almost radially symmetrical1 exhibits a slight tendency towards platyspermy4 ,evidence recently brought forward by ,nathorst#hji renders probable a connexion of a presumably radiospermic seed ,lagenospermum ,arberi#haj with the ,lower ,carboniferous fronds ,adiantites bellidulus ,heer1 and this furnishes an interesting illustration of the association of both platyspermic and radiospermic seeds with the same generic type of foliage4 ,while retaining ,radiosperm and ,platysperm as convenient descriptive terms1 ,i have not adopted them as group-designations on the ground that they do not in themselves serve as trustworthy criteria of relationship4 ,attention is called by ,salisbury#haa to the occurrence of bilaterally and radially symmetrical fruits among ,british ,carices and to a similar mixture in the family ,polygonaceae4 ,the acquisition of more detailed and accurate knowledge of ,palaeozoic seeds led to an extension of the two-fold division of ,brongniart and ,oliver which is based on such characters as the position of the vascular tissue in relation to the integument and nucellus1 the form of the pollen-chamber1 and other features4 ,the division ,lagenostomales has been instituted for ,lagenostoma and some other ,radiosperms connected by certain important characters3 these seeds may be referred to the ,pteridospermeae though it is only in the case of ,lagenostoma1 and to a less extent ,sphaerostoma1 that a correlation between vegetative organs and seeds has been rendered sufficiently probable to justify an assumption of generic identity4 ,the name ,trigonocarpeae#hab has recently been used for a section of ,radiosperms represented by ,trigonocarpus1 ,stephanospermum1 and other genera4 ,although the genus ,stephanospermum1 as ,oliver#hac says1 may be regarded as the type-genus of a group of seeds1 it is more fitting1 as the same author#had insists1 to adopt a divisional term based on the generic name of the much more widely spread and more familiar ,trigonocarpus4 ,for the sake of uniformity in nomenclature it is proposed to adopt the name ,trigonocarpales instead of ,trigonocarpeae to rank with ,lagenostomales4 ,the ,platyspermeae comprise such seeds as ,cardiocarpus1 ,mitrospermum1 and ,rhabdospermum1 genera characterised by well-marked anatomical features and probably ,cordaitean2 it has1 however1 been shown that typical ,platysperms were also borne on leaves of ,pteridosperms and1 as ,mrs ,arber#hae says1 the notion that every member of the ,platyspermeae was necessarily a ,cordaitean seed has been discredited by the discovery of the seeds of ,aneimites 7,wardia7 and ,pecopteris ,pluckeneti#haf4 ,for general purposes it is hardly necessary to adopt the subdivisions of the ,lagenostomales used by ,oliver and ,salisbury#hag1 though as facts accumulate we shall no doubt be able to make further advances towards a natural system of classification4 ,the following three divisions of ,permo-,carboniferous seeds include genera founded on petrified specimens and thus afford valuable morphological data4 ,the groups ,lagenostomales and ,trigonocarpales include types belonging to closely related plants1 a relationship clearly expressed in the seed-characters4 ,i4 ,lagenostomales4 ,the seeds included in this group are for the most part ,radiosperms1 but in its slightly developed bilateral symmetry ,conostoma oblongum is a type transitional between ,radiosperms and ,platysperms4 ,the testa may be ribbed and the ribs vary in number4 ,the nucellus 7megasporangium7 is united to the integument not only at the base but laterally as far as the shoulder of the seed up to a level corresponding to the base of the pollen-chamber 7lagenostome7 as in all recent ,cycads and in the majority of ,conifers4 ,the seeds proper apart from the cupule are supplied with a single set of vascular bundles2 there is no vascular tissue in the nucellus1 a feature no doubt correlated with the fusion of nucellus and integument#hah4 ,the free portion of the integument is more or less deeply lobed or1 in ,lagenostoma1 it forms a pyramidal canopy of fused lobes enclosing the lagenostome4 ,the presence of a tapetal zone surrounding the megaspore is believed to be a feature characteristic of the group#hai4 ,the testa1 wholly or partially ribbed1 is relatively thinner than in the ,trigonocarpales and ,cardiocarpales1 and in its differentiation agrees less closely with the testa of recent ,cycadean seeds4 ,in ,lagenostoma and possibly in other genera a loose sheath or cupule surrounded the ovule1 while in ,gnetopsis a similar envelope enclosed two to four seeds4 ,the microspores are multicellular and smaller than those of ,trigonocarpales1 the average dimensions 7,conostoma1 ,physostoma1 ,lagenostoma7 being #fg #eb4 ,genera4 ,physostoma2 ,conostoma2 ,sphaerostoma2 ,lagenostoma2 ,gnetopsis4 ,lagenostoma may safely be referred to ,lyginopteris1 and ,sphaerostoma with but little risk of error to ,heterangium3 the parent-plants of the other genera are unknown1 but all may be regarded as the seeds of ,pteridosperms and probably of genera more nearly allied to the ,lyginopterideae than to the ,medulloseae4 ,the genus ,lagenospermum1 recently instituted by ,nathorst#hbj1 is dealt with in ,chapter xxxi4 ,physostoma4 ,williamson4 ,physostoma elegans ,williamson4 ,the generic name ,physostoma#hba was applied by ,williamson#hbb to a seed from the ,lower ,coal ,measures of ,lancashire which he named ,p4 elegans2 he afterwards described it as ,lagenostoma physoides1 but the original name has been revived by ,oliver#hbc to whom our knowledge of this type is chiefly due4 ,the specimens figured by ,williamson#hbd as ,sporocarpon ornatum also belong to ,physostoma elegans4 ,the seeds are circular in section1 approximately #f mm4 long with a maximum diameter of #b mm4 ,the testa has about #aj longitudinal ribs passing in the apical region into a ring of free lobes or tentacles surrounding and considerably overtopping the nucellar apex3 these tentacles take the place of a micropylar tube 7fig4 #did1 ,i2 fig4 #dic1 ,d7 and are a feature #8in which this seed differs from all other known seeds1 fossil or recent#hbe4' ,a single vascular strand passes through the chalazal region and divides into #aj bundles1 one to each rib and tentacle4 ,the single integument consists of a few layers of cells1 those of the epidermis being prolonged into clavate mucilaginous hairs1 fig4 #did1 ,i1 h1 that may reach a length of #e mm4 and in the living seed almost covered the whole surface of the testa1 being especially long on the ribs and tentacles4 ,there is no special development of sclerous tissue1 the vascular bundles1 v1 being embedded in parenchyma in the inner portion of the integument4 ,the nucellus is represented by a zone rich in secretory cells1 and internal to this is a tapetum4 ,integument and nucellus are coalescent up to the apical region where the former splits into #aj tentacles4 ,the nucellar apex has the form of a tall dome surrounded by a bell-shaped pollen-chamber 7fig4 #did1 ,i1 pc2 fig4 #dic1 ,c1 ,d1 c7 into which it projects like the base of a wine-bottle4 ,the circular opening of the pollen-chamber overtops the roof of the dome formed of the secretory tissue of the nucellus and the carbonised remains of the tapetum3 this dark band surrounds the large megaspore-cavity 7fig4 #did1 ,i74 ,physostoma is the only member of the ,lagenostomales in which the megaspore projects into the free nucellar apex3 in other genera intercalary growth has produced a more or less prominent plinth1 the name given to the free portion of the nucellus between the megaspore and the pollen-chamber4 ,williamson#hbf described the mammillated apex of the nucellus as pushed up into the base of the lagenostome which #8looks like a bladder half full of fluid resting upon and overhanging the end of a soda-water bottle'3 it was this appearance that suggested the name ,physostoma4 ,the section reproduced in fig4 #dic1 ,d1 shows in the centre the limiting tissue of the nucellus surrounded by the pollen-chamber1 c1 and external to this are the tentacles with their groups of long hairs3 the vascular bundles are represented by spaces in the more internal small-celled tissue 7see also fig4 #did1 ,i74 ,a characteristic feature is the presence of a tapetum or megaspore-jacket#hbg in the nucellus3 immediately internal to the vascular bundles stretching from the chalaza to the apex of the megaspore-cavity is a layer of delicate cells with secretory sacs1 and this is succeeded by a broad black layer of rather larger cells1 a tissue which was probably in full activity in a younger stage of development4 ,illustration3 ,fig4 #dic4 ,a1 ,lagenostoma ovoides1 longitudinal section of the lagenostome4 ,b1 ,lagenostoma ,lomaxi1 transverse section of the lagenostome and canopy2 c1 pollen-chamber2 d1 space between the nucellus and integument4 7,a1 after ,miss ,prankerd2 ,b1 from a section in the ,manchester ,museum1 ,r #ajdh47 ,c1 ,physostoma elegans1 longitudinal section showing microspores in the pollen-chamber1 c4 7,from a section in the ,university ,college ,collection47 ,d1 ,physostoma elegans1 transverse section of the apical region showing the tentacles1 pollen-chamber1 c1 etc4 ,e1 ,telangium ,scotti1 transverse section of sporangia 7,manchester ,coll4 ,r #ajdg74 ,f1 ,g1 ,stephanospermum akenioides4 ,f1 section of sclerotesta4 ,g1 tracheids from the nucellus4 7,university ,college ,coll47 ,a comparable tapetal layer is described by ,lang#hbh in the ovule of ,stangeria3 the majority of the sporogenous cells surrounding the megaspore become disintegrated and are absorbed1 but the outermost zone forms a more definite tapetal layer3 as already suggested1 this tissue in ,physostoma may be a group-character4 ,no archegonia have been found1 but in a few cases some of the delicate prothallus-tissue occurs in the interior of the seed4 ,microspores are often abundant in the pollen-chamber 7fig4 #dic1 ,c1 c72 in one seed #hj are recorded4 ,the occurrence of so many microspores suggested to ,oliver that insect-agency may have been responsible for the precision in pollination that is greater than one would expect in anemophilous plants4 ,the spores are smaller than those of ,lagenostoma 7#ee #de7 and in several of them the remains of a cellular tissue are preserved 7fig4 #did1 ,n71 also some sub-reniform bodies 7fig4 #did1 ,m7 similar to those described as spermatozoids by ,dr ,benson in ,lagenostoma 7fig4 #djh1 ,d74 ,the most interesting features of ,physostoma are3 the absence of a continuous micropylar tube and its replacement by a circle of integumental lobes2 the apical prolongation of the nucellar apex into the pollen-chamber1 and the presence of long mucilaginous hairs on the integument4 ,the large pollen-chamber is a character which distinguishes ,physostoma from ,conostoma and its form is very different from that in ,lagenostoma4 ,the tentacles of the integument and the form of the nucellar apex are features consistent with ,oliver's view that ,physostoma is the most primitive of ,palaeozoic seeds though1 as ,burlingame#hbi says1 the elaborate form of the encasing envelope marks a considerable advance beyond the earliest type of megasporangium integument4 ,a new type of ,physostoma has been briefly described by ,gordon#hcj1 without a specific designation1 from the ,lower ,carboniferous beds of ,pettycur 7,fife73 it was found in association with ,heterangium and ,sphaerostoma ovale4 ,we have no knowledge of the plant to which ,physostoma belonged1 but the general plan of organisation of the seed points to a near relationship to ,lagenostoma and presumably1 as regards the parent-plant1 to a genus related to ,lyginopteris4 ,conostoma4 ,williamson4 ,this name#hca1 suggested by the funnel-like pollen-chamber or lagenostome1 was applied by ,williamson#hcb to some seeds from the ,lower ,coal ,measures of ,lancashire and ,yorkshire and from the ,lower ,carboniferous beds of ,burntisland4 ,the ,burntisland seeds1 referred by ,williamson to two species1 have recently been united and described by ,miss ,benson as ,sphaerostoma ovale#hcc4 ,the ,english species has been thoroughly investigated by ,oliver and ,salisbury#hcd who have also described a second species1 ,c4 anglo-germanicum1 from the ,coal ,measures of ,lancashire and ,germany4 ,conostoma oblongum ,williamson4 ,this rare type is represented by approximately cylindrical seeds with an average length of #e mm4 and a maximum breadth of #bc mm4 borne on a relatively stout stalk and tapering to a blunt apex characterised by a canopy of six short lobes 7fig4 #did1 ,b1 ,c7 in marked contrast to the long tentacles of ,physostoma4 ,in the basal region the integument has six prominent ribs which soon die out when traced upwards3 a transverse section through the body of the seed is hexagonal 7fig4 #did1 ,d71 the angles corresponding to the basal ribs1 and there is a slight tendency to platyspermy4 ,the testa has an epidermal mucilaginous layer which becomes exfoliated through the lifting-up of the cuticle by the underlying mucilage3 below this1 at the apex of the seed1 is a cap of fleshy tissue 7fig4 #did1 ,b1 sa7 which1 it is suggested1 may have had a secretory function in connexion with a drop-mechanism in pollination like that in recent ,conifers4 ,no microspores have been found in the pollen-chamber4 ,the epidermis1 called by ,oliver and ,salisbury the blow-off layer 7fig4 #did1 ,b1 m71 together with the cap of soft tissue constitute a feebly developed sarcotesta4 ,a sclerotesta consisting of a palisade-layer and a fibrous hypoderm extends over the main body of the seed below the epidermis2 it forms the basal ribs and increases considerably in breadth at the apical region to form a sclerous cone penetrated by six strands of parenchyma enclosing vascular bundles 7fig4 #did1 ,d7 which pass up from the conducting tissue immediately external to the nucellus4 ,the nucellus is coalescent with the integument1 as in ,physostoma1 as far as the level of the domical free apex of the nucellus where the tapetal tissue that lines the seed-cavity passes across the almost flat top of the central region originally occupied by the megaspore4 ,in some sections prothallus-tissue was found with an apical #8tent-pole' protuberance4 ,a striking feature of ,conostoma is the mechanism for the reception of the microspores4 ,the free part of the nucellus consists of the plinth1 a broad tapering region originally filled with parenchyma but in most cases represented only by its epidermis3 the plinth1 p1 is seen in fig4 #did1 ,b1 to be two-storeyed1 the upper and narrower storey being a space formerly filled by a pad of tissue suspended from the floor of the superposed lagenostome 7pollen-chamber7#hce4 ,the greater development of the domical plinth is a feature in which ,conostoma differs from ,physostoma4 ,at the apex of the plinth and resting on a slight depression is a small lagenostome1 bowl-shaped in section1 and like the pollen-chamber of ,lagenostoma1 formed as the result of enzyme-action on the apical papilla of the nucellus 7fig4 #did1 ,b1 ,b1 l74 ,the mouth of the lagenostome engages with the micropylar tube by a projecting flange 7fig4 #did1 ,b1 f7 of tissue lining the micropylar canal and by a second flange 7f7 at the base of the lagenostome where the roof of the plinth 7fig4 #did1 ,b1 p7 bends downwards and inwards4 ,the walls of the lagenostome are formed by strong cells with thickening bands giving them the appearance of tracheids 7l71 but the floor of the lagenostome is made of thinner cells which become disorganised1 allowing the microspores to fall into the large plinth-cavity below 7p1 fig4 #did1 ,b71 an arrangement comparable with the two-storeyed pollen-chamber of ,bowenia#hcf and1 to a less extent1 with the micropyle of the ,conifer ,tsuga4 ,the microspores are multicellular and ellipsoidal measuring #ge #fe4 ,illustration3 ,fig4 #did4 ,a1 ,stephanospermum akenioides2 s1 space between integument and nucellus2 n1 nucellus2 e1 inner part of testa2 sc1 sclerotesta2 t1 t1 tracheidal mantle2 pc1 pollen-chamber2 a1 archegonia2 td1 tracheidal pad4 ,b-,d1 ,conostoma oblongum2 a1 level of the transverse section shown in fig4 ,c2 b1 level of transverse section ,d2 m1 lobes of tissue surrounding the micropyle2 sa1 sarcotesta2 v1 vascular bundles2 p1 plinth4 ,b1 section of lagenostome and part of the integument2 f1 f1 flanges2 l1 wall of micropyle-funnel4 ,e1 ,f1 ,g1 ,gnetopsis elliptica2 t1 tent-pole4 ,f1 section of the plumes4 ,g1 section through the lagenostome4 ,h1 ,gnetopsis from ,barnsley1 ,yorkshire1 slightly enlarged4 ,i1 ,physostoma elegans2 h1 hairs4 ,k1 ,l1 ,mitrospermum compressum2 cf1 inner flesh2 n1 nucellus and megaspore4 ,l1 transverse section4 ,m1 microspores and 787 male gametes of ,physostoma elegans4 ,n1 microspore of ,physostoma showing part of exine and the internal cells4 7,a-,i1 ,n1 ,m1 after ,oliver2 ,h1 ,kidston ,coll4 ,no4 #abee2 ,k1 ,l1 after ,mrs ,arber47 ,the species ,conostoma anglo-germanicum agrees closely with ,c4 oblongum in general form and organisation1 but it has eight ribs1 four more prominent than the others1 and differs also in other minor characters from the rather shorter seeds of the type-species4 ,conostoma differs from ,lagenostoma in the absence of the tubular prolongation of the lagenostome1 the micropyle being like that in recent ,gymnosperms4 ,in ,conostoma the tracheid-like elements of the lateral wall of the lagenostome are a characteristic feature1 and no evidence has been found of the existence of a central core of tissue such as occupies the centre of the seed-apex in ,lagenostoma4 ,the long hairs of ,physostoma are represented in ,conostoma by the much smaller mucilaginous cells of the epidermis and in ,lagenostoma by the less closely united mucilage-cells of the superficial layer of the testa4 ,sphaerostoma4 ,benson4 ,as already pointed out in ,chapter xxix4 where this genus is described as probably the seed of ,heterangium1 there is a fairly close general resemblance between ,sphaerostoma and ,lagenostoma4 ,in the presence of free apical lobes the former genus resembles ,conostoma1 and while agreeing with ,lagenostoma in its annular pollen-chamber it is peculiar in the retention of an epidermis over the roof of the pollen-chamber3 as in ,lagenostoma the seed is enclosed by an outer integument or cupule4 ,lagenostoma4 ,williamson4 ,an account of this type of seed is included in the description of ,lyginopteris#hcg4 ,the more striking peculiarities are exhibited by the pollen-chamber and the free region of the integument3 the annular pollen-chamber 7fig4 #dic1 ,d1 c2 fig4 #dji7 surrounds a central nucellar cone and is prolonged upwards as a tube engaging with the micropyle in contrast to the form of the pollen-chamber and the absence of a tubular prolongation in ,conostoma4 ,the tentacles of ,physostoma and the short apical lobes of ,conostoma are replaced by an apical cone formed by the coalescence of the integument containing nine cavities originally filled with parenchyma 7figs4 #dji2 #dic1 ,b74 ,the presence of a cupule is a characteristic feature of young seeds1 but from negative evidence in the case of most other seeds it is unsafe to assume that the cupule of ,lagenostoma is an exceptional feature4 ,the nucellus and testa are united as far as the shoulders of the seed as in the seeds of recent ,cycads and in contrast to their lateral independence in ,trigonocarpus1 ,stephanospermum1 and other genera4 ,gnetopsis4 ,renault4 ,this generic name was given by ,renault#hch to some small petrified seeds from the ,stephanian of ,grand' ,croix and to impressions from the ,commentry coal-field which he believed to belong to some ,gnetaceous plant4 ,saporta and ,marion#hci and other authors have accepted these seeds as evidence of the existence of ,palaeozoic ,gnetales3 it has1 however1 been shown#hdj that ,gnetopsis has no claim to such relationship and is a type of seed closely allied to ,conostoma4 ,renault described three species1 afterwards adding three from another locality#hda2 the genus is recorded also from ,commentry#hdb and ,gard#hdc4 ,more recently ,depape and ,carpentier#hdd have described examples from the ,westphalian of ,valenciennes which they place in the ,pteridosperms in accordance with the conclusion of ,oliver and ,salisbury4 ,gnetopsis has also been discovered by ,mr ,hemingway in the ,middle ,coal ,measures of ,england#hde 7fig4 #did1 ,h74 ,gnetopsis elliptica ,renault4 ,the seeds of this species1 slightly oval in section1 occur in groups of #b-d in a cupular investment 7fig4 #ejf1 ,e1 p4 #cei7 described by ,renault as an ovary but correlated by ,oliver and ,salisbury with the cupule which surrounds the single ovule of ,lagenostoma4 ,the cupule is lined with hairs similar to those on the wall of the cupule of ,lagenostoma4 ,a characteristic feature of the ,french seeds is the presence of three or four long plumes of hairs at the apex 7fig4 #did1 ,e1 ,f74 ,as seen in fig4 #did1 ,e1 a small lagenostome 7pollen-chamber7 rests on the roof of a broad plinth precisely as in ,conostoma1 and four vascular bundles1 corresponding to the six bundles in ,conostoma1 pass into the apical cap of sclerous tissue enclosed by a sarcotesta1 sa 7fig4 #did1 ,e1 ,g74 ,a #8tent-pole' prolongation 7fig4 #did1 ,e1 t7 occurs at the apex of the prothallus4 ,renault described a portion of the integument as consisting of lacunar tissue which ,oliver and ,salisbury homologise with the superficial mucilaginous layer of ,conostoma3 this is seen above the sclerotesta in the apical region of fig4 #did1 ,e1 sa4 ,gnetopsis anglica ,kidston ,,ms4 ,this species 7fig4 #did1 ,h7 is represented by seeds from the ,middle ,coal ,measures near ,barnsley1 ,yorkshire1 #d mm4 long with apical appendages at least #bb cm4 in length and probably four in number4 ,the appendages do not show the hairs which form a prominent feature in the ,french specimens1 but this is probably the result of imperfect preservation3 there are indications of hairs on other specimens in ,dr ,kidston's ,collection4 ,the type-specimen1 in ,dr ,kidston's ,collection1 was generously lent to me for examination4 ,gnetopsis1 while agreeing with ,conostoma in the more important features1 is distinguished by the apical plumes1 the very slight development of a tent-pole prolongation of the nucellar apex 7fig4 #did1 ,e1 t71 the smaller number of vascular bundles1 and by the presence of an enclosing cupule 7fig4 #ejf1 ,e74 ,in its slight departure from radial symmetry ,gnetopsis forms a transition between the ,radiospermeae and the ,platyspermeae4 ,it is undoubtedly the seed of a ,pteridosperm1 but nothing is known as to the nature of the vegetative organs of the parent-plant4 ,,ii4 ,trigonocarpales4 ,in this group are included radially symmetrical seeds for the most part belonging to members of the ,medulloseae4 ,the peripheral zone of the nucellus is supplied with vascular tissue and the nucellus is free within the integument except at the base2 it is superior and not semi-inferior#hdf as in recent ,cycads and in ,lagenostomales4 ,the ovule of ,myrica ,gale1 in which the nucellus stands free within the single integument1 affords an interesting parallel to seeds of this class in contrast to the usual ,angiospermous type with a laterally coalescent nucellus4 ,in ,myrica ,gale#hdg the vascular supply is confined to the integument4 ,there is a comparatively broad pollen-chamber and in some types the lateral tissue of the nucellus is prolonged as a tube within the micropyle4 ,the usually ribbed testa is differentiated into an outer flesh 7sarcotesta71 a sclerotesta1 and probably in most cases an endotesta or inner flesh4 ,the ribs of the sclerotesta are in the majority of genera in multiples of three and in position correspond to the outer ring of vascular bundles4 ,the presence of lacunar tissue in the sarcotesta of several genera may be correlated with dispersal by water4 ,the apical region of the integument is not lobed but extends as a longer or shorter micropylar tube above the summit of the nucellus4 ,in the differentiation of the testa1 the form of the pollen-chamber1 and in some other features1 the seeds of this group present a general agreement with those of recent ,cycads4 ,the microspores are multicellular and larger than those of the ,lagenostomales3 in ,stephanospermum akenioides they measure #afj #ajjhdh while in ,aetheotesta#hdi they reach #cfj #bij4 ,genera4 ,trigonocarpus2 ,tripterospermum2 ,ptychotesta2 ,hexapterospermum2 ,polypterospermum2 ,pachytesta2 ,stephanospermum2 ,polylophospermum2 ,codonospermum2 ,aetheotesta2 ,eriotesta2 ,gaudrya4 ,trigonocarpus4 ,brongniart4 ,a description of the morphological features of ,trigonocarpus ,parkinsoni and ,t4 shorensis is given in the chapter on ,medullosa 7p4 #aag71 as there is good evidence that they are the seeds of that genus4 ,there is considerable difference in size and to some extent in the form of casts included in ,trigonocarpus and1 in the absence of anatomical data1 it is hardly possible to determine the actual systematic position of many of the specimens so named4 ,dr ,arber#hej has recently proposed a new generic name ,schizospermum for casts very like those of ,t4 ,parkinsoni1 but distinguished by the splitting of the shell into three valves1 a character which leads him to conclude that it is the external surface which is preserved and not a mere cast of the seed-cavity4 ,it is1 however1 more probable that the specimens are casts of a split sclerotesta4 ,in ,trigonocarpus pusillus#hea the shell is divided into three valves1 the dividing lines being marked by greatly reduced ribs1 and in ,t4 schizocarpoides ,grand',eury#heb1 a species that may not be a true ,trigonocarpus1 there is also evidence of splitting4 ,arber points out that the species ,rhabdocarpus ,boschianus ,berg4 is founded on a ,trigonocarpus from which the outer flesh has disappeared leaving the shell as the external covering4 ,trigonocarpus seeds are widely distributed in ,carboniferous and ,permian rocks in ,europe and ,north ,america3 from the latter continent ,newberry#hec has described several different forms that afford good examples of the abundance and variety of the genus4 ,some of the specimens included by ,newberry#hed in ,trigonocarpus are probably distinct generic types3 his species ,t4 multicarinatus may be identical with the ribbed cast shown in fig4 #ejf1 ,a4 ,the casts described by ,lindley and ,hutton and by other authors as ,t4 ,dawesi#hee are nearly #e cm4 long1 and if these are correctly included in the genus they point to the occurrence of seeds much larger than the type-species4 ,the ,french species ,trigonocarpus pusillus#hef ,brongn41 one of the smallest ,palaeozoic seeds1 from #fe to #ae mm4 long1 differs from ,trigonocarpus ,parkinsoni and ,t4 shorensis in the absence of prominent ribs and in the much feebler development of the sarcotesta4 ,specimens of the ,german type ,t4 sporites ,weiss1 believed by some authors to be megaspores1 were described by ,zeiller#heg from ,valenciennes as seeds3 these are from #be to #ce mm4 long and have three small ribs4 ,zeiller quotes the presence of cell-outlines on the surface as evidence of their seed-nature1 but it may be that this feature represents a sculpturing of the exine of a spore4 ,typical ,trigonocarpus seeds agree in several morphological characters with those of recent ,cycads4 ,they differ in the lack of a lateral union between nucellus and integument2 the presence of nucellar tracheids1 though a feature shared with ,bowenia1 distinguishes them from the majority of recent ,cycadean seeds4 ,in the comparatively long and fleshy micropylar tube a seed of ,encephalartos ,lehmanni presents a fairly close resemblance to a ,trigonocarpus4 ,salisbury has pointed out that the three species ,t4 ,parkinsoni1 ,t4 shorensis1 ,t4 pusillus form a consecutive series illustrating the gradual disappearance of the secondary ribs that form a prominent feature in ,t4 ,parkinsoni2 but for a comparison of these with other types of fossil and recent seeds the reader is referred to ,salisbury's summary#heh4 ,tripterospermum4 ,brongniart4 ,the seed on which this genus was founded by ,brongniart#hei is clearly very closely related to ,trigonocarpus and1 as ,oliver#hfj says1 the distinguishing character described by the author of the genus is unimportant4 ,brongniart describes the type species1 ,t4 rostratum1 as characterised by the presence of three prominent wings composed of a testa differentiated into an inner hard tissue and an outer lacunar tissue4 ,it is1 however1 hardly possible to say whether the outer soft tissue was originally flattened in the form of #8wings' or pressed down on to the harder shell4 ,renault#hfa notes the association of seeds that he refers to this genus with the leaves of ,dorycordaites1 but apart from the improbability of any connexion between ,tripterospermum and ,cordaites1 ,renault's seeds are too imperfect to demonstrate their identity with ,brongniart's genus4 ,kidston#hfb has described an impression of a three-winged seed from the coal-field of ,staffordshire as ,tripterospermum ellipticum1 a form described on page #ceg as ,polypterocarpus anglicus 7fig4 #dif1 ,b74 ,ptychotesta4 ,brongniart4 ,the type-species of this genus#hfc1 ,ptychotesta tenuis#hfd1 about #c cm4 long1 is characterised by six very prominent flanges or wings formed by the fissured or folded sclerotesta 7fig4 #die1 ,b74 ,there is no information as to the vascular supply or other anatomical details4 ,it is not at all improbable that there is no real distinction between this genus and ,brongniart's genus ,hexapterospermum4 ,hexapterospermum4 ,brongniart4 ,in this genus ,brongniart#hfe included two species1 ,hexapterospermum stenopterum and ,h4 pachypterum3 the shell is hexagonal in transverse section1 each angle being prolonged as a narrow flange4 ,in one of the sections figured by ,brongniart 7fig4 #die1 ,e7 the ribs are not fissured3 this is said to be a feature distinguishing ,hexapterospermum from ,ptychotesta1 but the occurrence of a fissured rib in another section suggests that in the structure of the ribs there is no essential difference between the two genera4 ,in ,ptychotesta pachypterum the testa is prolonged at the chalazal end as in ,polylophospermum1 and it is possible that there is no generic difference4 ,williamson described a cast from the ,coal ,measures of ,lancashire as ,hexapterospermum ,hexagonocarpus ,noegerrathi#hff 7fig4 #ejf1 ,h71 but in the absence of anatomical characters it is preferable to avoid the use of ,brongniart's term and to assign them to ,renault's genus ,hexagonocarpus#hfg4 ,similarly the seeds referred by ,dr ,p4 ,bertrand#hfh to ,hexapterospermum may appropriately be included in the genus ,hexagonocarpus4 ,illustration3 ,fig4 #die4 ,a1 ,polypterospermum ,renaultii4 ,b1 ,ptychotesta tenuis4 ,c1 ,d1 ,polylophospermum stephanense2 sa1 sarcotesta2 s1 spaces2 v1 vascular bundles4 ,e1 ,hexapterospermum stenopterum4 ,f1 ,diplotesta avellana4 ,g1 ,taxospermum ,grneri4 ,h1 ,diplotesta ,grand',euryana4 7,after ,brongniart2 ,c1 after ,oliver47 ,polypterospermum4 ,brongniart4 ,this generic name was proposed for an ovoid seed from ,st tienne described as ,polypterospermum ,renaultii#hfi2 hexagonal in section with six deep and sharp flanges at the angles alternating with six secondary ridges distinguished by their blunter edges and slightly smaller depth 7fig4 #die1 ,a74 ,without further anatomical details it is hardly possible to say whether or not the species represents a well-defined generic type1 but it is not improbable that a fuller knowledge would confirm ,brongniart's institution of a new generic designation4 ,the seeds described by ,arber#hgj and ,kidston#hga respectively as ,radiospermum ornatum and ,polypterospermum ornatum are transferred to ,polygonocarpus on the ground that they afford no evidence of anatomical characters of the ,polypterospermum type4 ,pachytesta4 ,brongniart4 ,brongniart#hgb established this genus for some unusually large seeds 7fig4 #dif1 ,a7 from the ,coal ,measures of ,france reaching a length of #aa-ab cm4 and resembling in form and size a hen's egg4 ,petrified examples have been described by ,brongniart and ,renault#hgc1 and ,oliver#hgd has given a lucid statement of the more interesting features of this ,permo-,carboniferous genus4 ,pachytesta gigantea 7,grand',eury74 ,in the separation of nucellus and integument ,pachytesta agrees with ,stephanospermum and ,trigonocarpus4 ,there is a double series of vascular bundles in the outer part of the testa or exotesta 7fig4 #dig1 ex7 consisting of a spongy tissue bounded externally and internally by sclerotic layers3 the exotesta is succeeded by a broader endotesta of spongy consistency which ,renault suggested may have served as a floating mechanism1 and this is intimately associated with the nucellus by means of grooves engaging with short ridges 7fig4 #dig1 nr7 on the surface of the nucellar tissue4 ,the exotesta is divided into three valves by radial extensions of the sclerotic tissue 7b1 c1 fig4 #dig2 at a the exotesta is shown in an unsplit condition74 ,in connexion with each radial plate are two curved plates of fibrous tissue which extend towards the grooves in the endotesta 7fig4 #dig1 t73 as ,oliver suggests1 these plates may have served a mechanical purpose for the support of the bulky nucellus4 ,the peripheral region of the nucellus is supplied by several vascular bundles 7fig4 #dig1 n7 from the tracheal chalazal disc4 ,the exotesta is regarded by ,oliver as corresponding to the sarcotesta and sclerotesta of other seeds1 and the grooves in the endotesta interlocking with the nucellar ridges are compared with the interlocking of nucellus and canopy in ,lagenostoma1 as also with the ruminated endosperm of ,torreya4 ,illustration3 ,fig4 #dif4 ,a1 ,pachytesta incrassata4 ,b1 ,polypterocarpus anglicus4 7,a1 after ,renault2 ,b1 after ,kidston47 ,illustration3 ,fig4 #dig4 ,pachytesta4 ,transverse section of a seed showing the exotesta1 ex1 with sclerous layers and vascular strands 7black71 the endotesta 7dotted71 the nucellus with its ring of vascular bundles1 n1 and the prothallus1 p4 ,the three radial plates in the exotesta are seen at a1 b1 c1 with the trabeculae1 t1 and internal to these are the grooves in the endotesta engaging with ribs on the nucellus1 nr4 7,after ,oliver47 ,we have no definite information as to the plants which bore ,pachytesta1 but it is probable that they were members of the ,medulloseae4 ,grand',eury#hge believes ,pachytesta to be the seed of ,alethopteris ,grandini1 though this view requires confirmation4 ,this author figures several ,pachytesta seeds attached in two oblique rows to a comparatively slender axis which may be the rachis of a large compound frond#hgf4 ,renault and ,zeiller#hgg have figured specimens of ,p4 gigantea and ,p4 incrassata from ,commentry which afford a good idea of the form of these large seeds2 the genus is recorded also from ,gard1 ,blanzy#hgh1 and other localities4 ,kidston#hgi described a large oval seed1 blunt at each end1 from the ,middle ,coal ,measures of ,lancashire as ,carpolithus ,wildii which he thinks may be allied to ,pachytesta1 but adds1 #8,i do not think we are justified in placing mere impressions of plants in genera1 whose distinctive characters are derived from their internal organisation1 unless there is conclusive evidence to show their identity4' ,on this specimen ,arber#hhj has founded a new genus ,megalospermum1 but as the type-specimen shows no distinctive features other than large dimensions it would seem preferable to retain the more general designation ,carpolithus#hha4 ,another example of a seed that may be generically identical with ,pachytesta is that described by ,lesquereux from ,north ,american ,coal ,measures as ,rhabdocarpus ,mansfieldi and more recently recorded by ,white from ,missouri as ,rhabdocarpus 7,pachytesta7 ,mansfieldi#hhb4 ,there is little doubt that this and other species of seeds preserved as impressions are examples of ,pachytesta but1 as ,kidston says1 it is preferable to reserve the name for specimens showing anatomical features4 ,stephanospermum4 ,brongniart4 ,the genus ,stephanospermum1 founded by ,brongniart#hhc on petrified specimens from ,french ,stephanian beds1 affords a good example of a radiospermic seed without ribs differing in certain well-marked characters from such seeds as ,lagenostoma1 ,physostoma1 and ,conostoma1 notably in the complete separation of the nucellus from the integument and in the possession of a nucellar vascular system4 ,the descriptions by ,brongniart and ,renault#hhd have been extended by the thorough investigations of ,oliver#hhe4 ,stephanospermum akenioides ,brongniart4 ,this species is represented by ellipsoidal seeds1 #aj mm4 long with a maximum breadth of #d-de mm41 circular in transverse section4 ,the integument consists of a thick sclerotesta lined internally by a thinner soft layer1 the endotesta 7fig4 #did1 ,a1 sc1 e71 and in all probability covered by an outer flesh or sarcotesta as in ,trigonocarpus1 though this tissue is not preserved and is omitted from the section shown in fig4 #did1 ,a4 ,the sclerotesta is composed of a broad outer band of thick-walled palisade cells--the contracted contents of which are a striking feature in the silicified seeds 7fig4 #dic1 ,f72 these are succeeded by an inner zone of longitudinal fibres4 ,in the structure of the palisade-layer ,stephanospermum bears a close resemblance to the sporocarp wall of ,pilularia#hhf4 ,in the apical region the shell forms a circular ridge surrounding a peri-micropylar trough1 a character expressed by the term #8crown-seed#hhg' employed by ,grand',eury3 the trough sometimes contains partially destroyed tissue that may be a remnant of a sarcotesta4 ,a ,stephanospermum seed1 with its apical core and surrounding depression with remnants of some partially destroyed tissue1 may be compared with a fruit of ,attolia speciosa 7,palmae7 in which a tuft of fibrous tissue picked out by decay from the mesocarp surmounts the conically pointed apex of the harder interior of the fruit-wall4 ,the base of the sclerotesta is perforated by a vascular strand which expands into a tracheal disc1 td1 fig4 #did1 ,a1 at the base of the megaspore from which a continuous mantle #b-c cells broad1 of short spiral and scalariform tracheids 7fig4 #dic1 ,g71 spreads over the whole of the nucellus immediately below the nucellar epidermis as far as the lower part of the sides of the pollen-chamber3 this mantle forms the floor of the large domical pollen-chamber excavated out of the nucellar cone 7fig4 #did1 ,a1 pc74 ,the fact that in sections of older seeds the tracheal floor shows signs of splitting and disorganisation led ,oliver to conclude that in the living seed the tracheids underwent a gradual disintegration prior to fertilisation1 thus allowing the passage of the antherozoids to the egg-cells 7fig4 #did1 ,a1 a74 ,the presence of a continuous tracheal sheath instead of separate vascular bundles is a special feature in which ,stephanospermum differs from ,trigonocarpus and other ,palaeozoic seeds as well as from those of recent ,cycads2 as ,oliver suggests1 #8the apparent perfection of the vascular mantle in ,stephanospermum may have proved an obstacle to further development#hhh' and was not retained by the more successful types4 ,in its tracheal sheath ,stephanospermum resembles the seeds of ,ginkgo4 ,the nucellar cone is prolonged as a beak into the micropyle formed by the tubular integument4 ,the megaspore occupies the central portion of the seed and in the course of its development it compressed the megasporangium 7nucellus7 to such an extent that little more than the epidermis remains3 there is a definite megaspore-membrane surrounding the prothallus-tissue in which there were probably two archegonia 7fig4 #did1 ,a1 a7#hhi4 ,the nucellus stands free within the integument from which it is separated by a space 7s1 fig4 #did1 ,a74 ,microspores are frequently met with in the pollen-chamber in which they matured after their introduction through the micropyle1 probably with the aid of a drop of mucilage3 they are large oval bodies with an average size of #afj #ajj1 some reaching over #bjj1 in length and1 as ,renault was the first to point out1 within a finely granulate exospore there are several thin-walled cells3 this statement was not accepted by some authors but ,prof4 ,oliver's researches have amply confirmed it1 and an examination of the original preparations convinced me that ,renault had correctly described the structural features4 ,oliver shows that there are about #bj cells within each microspore regularly arranged as rows of five wedge-shaped elements with their pointed ends directed towards the centre1 and he thinks that these cells may have undergone further division to produce sperm-mother-cells1 though there is not such good evidence of this as in the differently constituted microspores of ,stephanospermum caryoides4 ,no trace of pollen-tubes was found and it is probable that the antherozoids were liberated by the rupture of the delicate prothallus-tissue4 ,the tracheal sheath afforded an adequate means of water-supply to the pollen-chamber and this enabled the motile antherozoids to reach the archegonia4 ,stephanospermum caryoides ,oliver#hij4 ,this species1 founded on a specimen from 41 is a larger seed 7#aee #abe mm47 and more globular than ,s4 akenioides2 there is a shorter micropylar beak and a less developed peri-micropylar trough4 ,as in ,s4 akenioides the nucellus is free from the base and the two species conform to the same general type of construction4 ,the microspores are distinguished by the presence of only two internal cells which do not occupy the whole of the spore-cavity but are surrounded by a large peripheral cell comparable with the tube-cell in recent microspores1 though there is no proof that a tube was formed3 in the case of ,s4 akenioides ,oliver considers that fertilisation was not assisted by the production of a pollen-tube4 ,the two cells by further division gave rise to a secondary cell-complex consisting of at least eight antherozoid-mother-cells4 ,no antherozoids have been found in the microspores but it is possible that two small bodies1 #ag #ae1 met with in a pollen-chamber may represent the nuclei of sperms4 ,their small size differentiates them from the much larger male gametes of ,cycads and from the supposed sperms of ,physostoma and ,lagenostoma4 ,we have no proof as to the nature of the plant which bore seeds of the ,stephanospermum type1 but it is significant that the specimens occur in close association with fragments of ,alethopteris and ,myeloxylon1 a circumstance that favours the view1 based on the resemblance of these seeds to ,trigonocarpus1 that ,stephanospermum is the seed of a member of the ,medulloseae4 ,polylophospermum#hia4 ,brongniart4 ,the type-species ,polylophospermum stephanense ,brongn4#hib1 founded on partially preserved material from ,grand' ,croix1 is a narrow hexagonal seed #ae mm4 long4 ,additional facts as to the structural features have been contributed by ,oliver#hic4 ,the testa is differentiated into an inner shell 7sclerotesta7 and an outer flesh 7sa1 fig4 #die1 ,c1 ,d73 the sclerotesta has six prominent1 fissured1 ribs1 one at each angle1 and between these are six solid and less prominent secondary ribs4 ,oliver states that there is an outer series of vascular bundles in the sarcotesta1 one bundle immediately external to each secondary rib 7fig4 #die1 ,c1 v74 ,in the presence of two kinds of ribs and in the relation of ribs to tracheal strands ,polylophospermum agrees with ,trigonocarpus ,parkinsoni4 ,strands of short tracheids supply the peripheral region of the nucellus and1 as in ,stephanospermum1 reticulate elements extend as far as the floor of the large pollen-chamber4 ,there was probably no lateral union between nucellus and integument4 ,a striking feature is the prolongation of the testa at each end of the seed to form an open chamber surrounding the micropylar beak and the seed-base 7fig4 #die1 ,d1 s1 s73 the apical chamber1 though relatively more prominent1 is comparable with that in ,stephanospermum1 while the basal chamber recalls that in the seed named by ,scott and ,maslen ,trigonocarpus ,oliveri#hid but subsequently removed by ,salisbury#hie from that genus4 ,there is no evidence as to the parent-plant of ,polylophospermum1 but it may be assumed to have been a ,pteridosperm1 probably one of the ,medulloseae4 ,illustration3 ,fig4 #dih4 ,a1 ,b1 ,codonospermum4 ,a1 ,c4 olivaeforme1 longitudinal section showing the seed-proper and the air-chamber1 s2 pc1 pollen-chamber4 ,b1 ,diagrammatic sketch of a ,codonospermum showing the vascular supply1 v1 and the fibrous arcs1 f1 in the wall of the lower part of the seed4 ,c1 ,aetheotesta elliptica1 s1 sarcotesta with lacunae2 v1 vascular supply4 7,after ,renault47 ,codonospermum#hif4 ,brongniart4 ,our knowledge of this peculiar genus is derived from ,brongniart's description of the type-species ,codonospermum anomalum#hig 7fig4 #ejf1 ,b1 ,c7 from ,st tienne and from ,renault's account of ,c4 olivaeforme#hih4 ,the seeds are globular or ellipsoidal and reach a length of #b cm43 the testa is differentiated into an outer flesh and a sclerotesta and has usually eight ribs4 ,the most striking feature is the division of the seed into two regions1 an upper portion containing the nucellus and megaspore and a lower portion in the form of an empty chamber that probably served as a float 7fig4 #dih1 ,a1 s74 ,externally the upper half or seed-proper forms a depressed cupola with eight slightly developed ribs1 separated by a circular transverse constriction from the basal chamber 7fig4 #dih1 ,b74 ,there is a fairly large pollen-chamber1 pc1 in which ,renault found multicellular microspores in ,c4 olivaeforme4 ,in ,c4 anomalum #af vascular bundles 7fig4 #dih1 ,b1 v7 surround the central region of the seed probably in the peripheral tissue of the nucellus2 these bundles unite in the chalazal region to form a strand that passes up the centre of the empty chamber4 ,in ,c4 anomalum the testa of the lower half has eight ribs and corresponding with each rib is a strand of fibrous tissue 7fig4 #dih1 ,b1 f74 ,in ,c4 olivaeforme the testa is thicker than in ,c4 anomalum and the lower region of the seed is smooth and circular in section4 ,impressions of ,codonospermum are described#hii from ,commentry1 from the ,loire--the ,gard district#ijj1 and by ,zeiller#ija from ,blanzy4 ,there is no decisive evidence as to the parent-plant1 but some ,french authors#ijb regard the frequent association of ,codonospermum with leaves of ,dolerophyllum as significant4 ,aetheotesta4 ,brongniart4 ,aetheotesta elliptica ,renault4 ,brongniart instituted the genus ,aetheotesta#ijc for an incomplete seed 7,a4 subglobosa7 from ,grand' ,croix1 and ,renault#ijd subsequently founded the species ,a4 elliptica on much better material4 ,the testa of the elliptical seed1 #c cm4 long1 consists of an outer region very thin on the flanks but highly developed at the apex and base which forms a sarcotesta characterised in the apical region by large radially disposed spaces1 fig4 #dih1 ,c1 s2 the sclerotesta1 composed of harder tissue1 is prolonged as an apical beak4 ,there is a large pollen-chamber1 pc1 in which ,renault found multicellular microspores 7#cbj-djj74 ,in the chalazal region the main vascular supply forms a cup-like investment1 v1 in the basal portion of the nucellus1 and at a higher level this breaks up into several nucellar strands4 ,renault thinks that ,aetheotesta is the seed of ,dolerophyllum1 but there is no proof of any connexion4 ,the presence of large spaces in the sarcotesta may be interpreted1 as ,renault suggests1 as evidence of adaptation to dispersal by water4 ,eriotesta4 ,brongniart4 ,brongniart#ije instituted this genus#ijf on an incomplete transverse section of a seed from ,grand' ,croix1 #h mm4 in diameter1 which he called ,eriotesta velutina1 characterised by a ribbed and probably octagonal testa bearing numerous elongated hairs over the whole surface4 ,the material is1 however1 too meagre to throw any light on the important features of the seed4 ,gaudrya4 ,grand',eury4 ,gaudrya trivalvis ,grand',eury4 ,the generic name ,gaudrya#ijg was proposed for two petrified seeds from the ,gard coal-field briefly described as ,g4 trivalvis1 the type-species1 and ,g4 lagenaria4 ,the testa of the former species shows signs of splitting along three equidistant lines2 it consists of a sarcotesta enclosing an endotesta with six longitudinal ribs3 ,grand',eury speaks of lacunae between the endotesta and nucellus which he regards as spaces in a tissue which made the seed buoyant and facilitated dispersal by water4 ,it is not clear whether the nucellus and integument were originally connected or laterally free3 the lacunae may be the remains of an inner flesh and not spaces in a spongy tissue4 ,the genus is radiospermic and characterised by a long micropyle and a broad pollen-chamber4 ,on the available evidence it is difficult to assign the specimens to their systematic position1 but the genus is probably a member of the ,trigonocarpales4 ,,iii4 ,cardiocarpales4 ,platyspermic seeds for the most part belonging to ,cordaitalean plants and agreeing in their plan of organisation1 even more closely than the seeds of the ,trigonocarpales1 with those of recent ,cycads4 ,the nucellus is free laterally from the integument and there is a series of vascular bundles in the nucellus4 ,the testa consists of an outer flesh1 the sarcotesta1 which may reach a considerable thickness1 a shell or sclerotesta1 and in some genera an endotesta4 ,in seeds preserved as impressions the sarcotesta often gives them a winged appearance 7,samaropsis74 ,the pollen-chamber is relatively small1 resembling in this respect the chamber in recent ,cycads4 ,a central prolongation of the prothallus-tissue in the form of a blunt column or #8tent-pole' is a characteristic feature2 the same feature occurs in seeds of the ,lagenostomales1 but in the ,cordaitales it resembles more nearly the #8tent-pole1' as it was called by ,hirase1 in recent ,cycadean seeds and in ,ginkgo4 ,the presence of two vascular strands in the sarcotesta in the principal plane of the seeds is a character shared with the seeds of ,cycas3 the position and course of these bundles are useful characters for distinguishing different types within the group4 ,the microspores are multicellular4 ,genera4 ,cardiocarpus2 ,cyclospermum2 ,cycadinocarpus2 ,rhabdospermum2 ,mitrospermum2 ,diplotesta2 ,leptocaryon2 ,taxospermum2 ,compsotesta4 ,these generic names are all used in the following pages for seeds known to possess certain anatomical features2 there are also included in the ,cardiocarpales the genera ,samaropsis1 ,cordaicarpus1 and ,rhabdocarpus1 but it is proposed to limit their use to specimens which furnish no anatomical data and cannot therefore be assigned with equal confidence to a section of seeds based on definite morphological characters4 ,it is certain that some at least of the seeds described under these names would1 if preserved as petrified specimens1 be included in one or other of the genera named above4 ,there is ample proof that some of these seeds were borne on ,cordaitean plants and that the group as a whole represents the seeds of the ,cordaitales#ijh4 ,it is1 however1 certain that some ,platyspermic seeds were produced by ,pteridosperms4 ,no little confusion has been caused by the employment of the same generic names for petrified seeds and for casts and impressions affording no evidence as to similarity in anatomical characters4 ,with a view to avoid the risks necessarily entailed by following this practice it is suggested that a clearer distinction should be drawn between genera based primarily on structural features and form-genera4 ,the following notes on the genera ,cardiocarpus1 ,cordaicarpus1 ,cyclocarpon1 ,cycadinocarpus1 ,jordania1 and ,samaropsis1 may serve to illustrate some of the difficulties connected with the terminology of ,palaeozoic seeds4 ,cardiocarpus4 ,brongniart#iji proposed the name ,cardiocarpon in #ahbh for ,upper ,carboniferous seeds described as compressed lenticular1 cordiform or reniform #8fruits' with an acute apex3 in his later work#iaj he recognised their true morphological nature and gave an account of some exceptionally well-preserved examples from ,grand' ,croix4 ,brongniart in common with other authors believed ,cardiocarpus seeds to belong to ,cordaitean plants1 a view that in several cases is based on conclusive evidence4 ,the specimen represented in fig4 #eja1 ,d1 illustrates the characteristic form of a cast of a ,cardiocarpus seed1 and the sections shown in fig4 #eja1 ,a and ,b1 are from an identical or a very closely allied species4 ,the generic characters are3 7i7 the presence of a narrow flattened border or wing surrounding a platyspermic nucule1 7ii7 the cordiform base and more or less pointed apex1 7iii7 the differentiation of the testa into a sarcotesta and sclerotesta free from the nucellus except at the base1 7iv7 the #8tent-pole' prolongation of the prothallus 7fig4 #eaj1 ,a1 b7 and the presence of a fairly large pollen-chamber1 pc1 7v7 the occurrence of two sets of vascular bundles1 an inner nucellar series and two double vascular strands 7fig4 #ejj1 ,a1 v1 ,b7 which are given off from the main supply before it reaches the sclerotesta4 ,the term ,cardiocarpus as used by ,brongniart signifies a type of seed possessing both certain anatomical and external characters4 ,the proposal is to restrict the generic appellation to seeds exhibiting definite structural features agreeing in essentials with ,cardiocarpus sclerotesta and ,c4 drupaceus4 ,cordaicarpus4 ,this name was first employed by ,geinitz#iaa in the form ,cordaicarpon1 the type-species being ,c4 ,cordai 7fig4 #ejb1 ,c7 from the ,coal ,measures of ,germany1 a seed referred by the author of the genus to ,cordaites principalis but1 as ,kidston has pointed out1 there is evidence that this correlation may be incorrect3 there is1 however1 no doubt as to its ,cordaitean parentage4 ,specimens included in this genus agree closely with species of ,cardiocarpus1 but they are usually described as being distinguished by the absence of a flat border and by a more rounded and less cordate base4 ,in the example of ,cordaicarpus ,cordai shown in fig4 #ejb1 ,c1 and in other species assigned by authors to this genus there is a narrow border and the form of the base is an inconstant character4 ,as ,kidston#iab and other authors point out1 there are no definite and constant characters by which to distinguish ,cardiocarpus from ,cordaicarpus as regards the form of the seeds preserved as casts or impressions4 ,a further account of ,cordaicarpus is given on a later page4 ,cordaispermum4 ,this designation was formerly adopted by ,renault#iac for seeds having the form and anatomical features of ,cardiocarpus which there is good reason for attributing to ,cordaites or to some allied genus4 ,in view of the fact that the majority of the seeds under consideration are undoubtedly ,cordaitean there is no need to employ this additional generic name4 ,cyclocarpon4 ,fiedler#iad instituted this term for seeds previously described by ,berger as ,cardiocarpon emarginatum 7fig4 #ejb1 ,b1 now included in ,samaropsis7 and added a new species ,cyclocarpon nummularium4 ,brongniart#iae subsequently described the structure of two species1 ,c4 tenue and ,c4 nummulare1 which he referred to ,fiedler's genus1 and ,bertrand#iaf has shown that these differ from the genus ,cardiocarpus in the recurrent course of the bundles given off from the chalazal strand as in the genus ,rhabdospermum 7cf4 fig4 #eja1 ,e74 ,there are no good grounds for retaining the designation ,cyclocarpon for casts and impressions1 as the specimens so named are indistinguishable from impressions referred to ,cordaicarpus4 ,the generic name ,cyclocarpus1 retained by ,bertrand only for ,c4 tenuis and ,c4 nummularis simply for anatomical reasons1 is now altered to ,cyclospermum on the ground that the designation ,cyclocarpon has been used for impressions affording no information with regard to anatomical features4 ,cycadinocarpus4 ,renault#iag transferred to this genus ,brongniart's species ,cardiocarpus augustodunensis on the ground that the vascular system exhibits in a greater degree than the other types included by ,brongniart in ,cardiocarpus a resemblance to that in recent cycadean seeds4 ,bertrand#iah confirms ,renault's account and retains ,cycadinocarpus augustodunensis as a species worthy of generic distinction4 ,a short account of this seed is given on a later page4 ,jordania4 ,this name was given by ,fiedler#iai to compressed ovate-cordate seeds characterised by a broad membranous border bearing a superficial resemblance to the seeds of ,bignonia4 ,the type-species1 ,j4 bignoniodes 7fig4 #ejb1 ,i71 from the ,coal ,measures of ,saarbrcken has the form usually associated with the designation ,samaropsis1 and as the latter term is generally adopted there are no adequate reasons for the retention of ,jordania4 ,the name ,jordania has also been applied1 by ,schenk#ibj1 to fossil ,dicotyledonous wood and was previously used by ,boissier#iba4 ,illustration3 ,fig4 #dii4 ,samaropsis emarginata1 from the ,westphalian series1 ,yorkshire4 7,kidston ,coll41 #dbbg2 #b47 ,samaropsis4 ,goeppert#ibb defined ,samaropsis as #8,fructus samaroideus membranaceus1 compressus1 margine alatus1 monospermus4' ,the type-species1 ,s4 ulmiformis1 from the ,permian of ,brenau1 is a small seed with a broad wing or border1 but a better example of ,samaropsis is figured by ,goeppert as the wing of an insect#ibc4 ,examples of the genus are shown in figs4 #ejb1 ,a-,h2 #ejc2 #ejd4 ,seeds included in ,samaropsis differ from those referred to ,cordaicarpus in the presence of a broader and more clearly defined border which in some cases1 as in the genus ,mitrospermum 7fig4 #did1 ,k1 ,l71 undoubtedly represents a lateral wing-like extension of the sarcotesta4 ,in some instances the wing may be a tangentially expanded integument comparable with the perianth of ,welwitschia1 and in some ,jurassic seeds referred by ,heer#ibd to ,samaropsis the lateral appendages are probably true wings4 ,it is advisable to restrict the designation ,samaropsis to ,palaeozoic seeds4 ,nucules deprived of the broad border would be referred to ,cordaicarpus as usually employed for impressions4 ,the generic name ,samaropsis serves a useful purpose as a distinctive term for platyspermic seeds preserved as casts or impressions characterised by the possession of a wide border or wing broader than in typical examples of ,cordaicarpus4 ,the specimen represented in fig4 #dii affords a good illustration of the difference between ,samaropsis and ,cordaicarpus4 ,in this specimen the border clearly consists of two portions1 an inner narrower border 7black in the drawing7 and an outer more delicate portion2 the former is the impression of the sclerotesta and the outer represents the fleshy sarcotesta which in the living seed may have formed a wing4 ,if1 as often happens1 the seed were preserved with the narrow border only it would be assigned to ,cordaicarpus1 many species of which are undoubtedly incomplete ,samaropsis seeds4 ,the seeds described by ,lindley and ,hutton as ,cardiocarpon acutum 7fig4 #ddd1 p4 #aga7 have been made by ,arber#ibe the type of a new genus ,cornucarpus1 the distinguishing feature being the triangular form and the apical horns of the wing4 ,the seeds figured by ,arber#ibf from the ,kent coalfield as ,cornucarpus acutus are1 however1 not identical with the type of ,lindley and ,hutton1 which has the characters of ,samaropsis4 ,samaropsis is widely distributed in ,permo-,carboniferous rocks in ,europe and ,north ,america and is recorded also from ,india#ibg 7fig4 #ejd71 ,china#ibh1 ,south ,africa#ibi 7fig4 #ejc71 ,south ,america#icj 7fig4 #ejb1 ,f1 ,g7 and ,australia#ica4 ,some seeds of this form were certainly borne on ,cordaitean plants 7cf4 fig4 #dhj1 ,a71 but seeds of similar type have been found in organic connexion with the foliage of ,pteridosperms 7figs4 #ddb1 #dde1 pp4 #afg1 #agb74 ,the ,permian #8cone-scales' bearing seeds described by ,geinitz as ,cardiocarpon triangulare#icb1 represented by well preserved impressions in the ,dresden ,museum1 appear to be of the ,samaropsis type3 the same author referred some ,samaropsis seeds to the ,conifer ,walchia1 but ,weiss#icc dissents from this correlation as the seeds often occur in beds in which ,walchia is not represented4 ,renault states that the seeds of the fertile shoot described by him as ,cycadospadix ,milleryensis#icd from ,autun ,strobilites ,milleryensis 7,ren47 closely resemble ,samaropsis fluitans ,daws4 as figured by ,weiss4 ,the suggestion by ,white#ice that ,samaropsis seeds were borne on fertile leaves of ,gangamopteris adds a further difficulty to the use of the generic characters of ,samaropsis as criteria of systematic position4 ,the ,permian seeds figured by ,goeppert#icf as ,oreodoxites ,martianus are possibly specimens of ,samaropsis4 ,the designation ,samaropsis1 though usually restricted to ,palaeozoic species1 is applied by some authors to #8winged' seeds from ,mesozoic strata2 but as some of the ,jurassic seeds#icg so named appear to have true wings like those of some recent ,conifers it is advisable to adhere to the more limited use of the name4 ,it is safe to assert that many ,samaropsis seeds agreed generally in structure with ,cordaitean seeds such as the petrified examples described by ,brongniart as ,cardiocarpus4 ,the species ,mitrospermum compressum#ich is an example of a petrified seed having the external features of ,samaropsis4 ,cardiocarpus4 ,this generic title ,i propose to restrict to petrified seeds exhibiting the characters described by ,brongniart#ici and more recently by ,bertrand#idj in ,c4 sclerotesta and ,c4 drupaceus4 ,in general organisation seeds of this generic type agree with those of recent ,cycads and with the seed of ,ginkgo biloba1 but there are certain distinguishing features4 ,an important character is afforded by the course and place of origin of the lower vascular strands from the main supply at the base of the seed4 ,the outer vascular system consists of two bundles given off from the main strand1 before it reaches the sclerotesta1 which pass up the sarcotesta 7fig4 #ejj1 ,b74 ,in ,rhabdospermum1 on the other hand1 the corresponding bundles arise at a higher level and form recurrent strands which penetrate the sclerotesta before passing up the fleshy part of the integument 7cf4 fig4 #eja1 ,e74 ,illustration3 ,fig4 #ejj4 ,cardiocarpus drupaceus var4 expansus4 ,a1 transverse section of the testa approximately in the middle of the seed2 v1 vascular bundles4 ,b1 diagrammatic sketch1 adapted from ,brongniart's drawing of the base of the seed showing the sarcotesta1 sa1 the sclerotesta1 sc1 and the pad of vascular tissue1 d1 at the base of the nucellus4 7,after ,brongniart47 ,cardiocarpus sclerotesta ,brongniart4 ,the testa is differentiated into an inner shell and an outer sarcotesta 7fig4 #eja1 ,a2 the sclerotesta is shown in black72 there is a well developed pollen-chamber 7pc7 and below this the prothallus-tissue is prolonged as a blunt and short tent-pole1 b1 as in ,gingko and in several fossil seeds4 ,on each side of the apical tent-pole the slightly shrunken prothallus shows two small archegonia1 a1 which in the relatively small size and spherical form of the egg-cells resemble those of ,ginkgo4 ,in transverse section 7fig4 #eja1 ,b7 the seed is bi-convex and at each end of the major axis the sclerotesta forms a small keel4 ,there are two sets of vascular bundles concerned in the supply of material to the ovule2 a lower pair of bundles given off from the central strand in the sarcotesta 7fig4 #ejj1 ,b7 which pass to the apical region in the inner tissues of the sarcotesta in the principal plane 7fig4 #ejj1 ,a1 v71 and an inner set of bundles that pass up the peripheral tissue of the nucellus4 ,the species described by ,brongniart as ,cardiocarpus 7,cyclocarpus7 tenuis and ,c4 nummularis have been removed by ,bertrand#ida from ,cardiocarpus on the ground that the integumental bundles pursue a course like that in ,rhabdospermum2 it is now referred to the new genus ,cyclospermum#idb4 ,illustration3 ,fig4 #eja4 ,a1 ,cardiocarpus sclerotesta in longitudinal section2 pc1 pollen-chamber1 b1 tent-pole1 a1 archegonia4 ,b1 transverse section2 a1 archegonia4 ,d1 cast of the same or a similar type of seed4 ,c1 ,e1 ,rhabdospermum cyclocaryon1 longitudinal section and a diagrammatic sketch of the seed-base2 m1 micropyle2 b1 tent-pole2 a1 archegonium4 7,a1 ,b1 ,c1 after ,brongniart2 ,d1 after ,renault and ,zeiller2 ,e1 adapted from ,brongniart47 ,cyclospermum4 ,gen4 nov4 7 ,cyclocarpus ,bertrand74 ,as stated on a previous page ,bertrand#idc re-establishes the generic name ,cyclocarpus1 founded on impressions without reference to anatomical characters1 for two petrified seeds from ,st tienne described by ,brongniart as ,cardiocarpus tenuis and ,cyclocarpus nummularis#idd4 ,these types differ from ,rhabdospermum in the absence of an apical snout but agree with that genus in the steeply descending course of the vascular strands in the basal region of the seed4 ,as stated on a previous page1 the name ,cyclospermum is proposed as a substitute for ,cyclocarpus because of the employment of the latter term for impressions4 ,cycadinocarpus4 ,schimper#ide4 ,cycadinocarpus augustudunensis 7,brongniart#idf74 ,in the possession of two sets of vascular bundles this type agrees with ,cardiocarpus1 but the more internal strands pass up on the inner face of the sclerotesta without penetrating into the nucellus1 a feature in which ,cycadinocarpus agrees with the majority of recent cycadean seeds3 the outer bundles are given off from the main supply after it has entered the sclerotesta and not before as in ,cardiocarpus2 they follow an oblique course in the sclerotesta and emerge into the sarcotesta at the shoulders of the basal curve of the seed4 ,as in ,cardiocarpus and ,rhabdospermum the two outer bundles lie in the principal plane of the seed4 ,there is a pollen-chamber at the apex of the nucellus and the latter tissue is prolonged as a tent-pole which engages with the micropyle4 ,in the absence of data as to the course of the vascular bundles in the chalazal region it would not be possible to distinguish between this genus and ,cardiocarpus4 ,rhabdocarpus ,berger and ,rhabdospermum gen4 nov4 ,it is proposed to restrict the name ,rhabdocarpus#idg to impressions and casts of seeds of the type represented by ,r4 tunicatus as figured by ,berger#idh and reproduced in fig4 #ejf1 ,k1 the term ,rhabdospermum being applied to seeds of similar form in which are shown certain distinguishing anatomical features4 ,rhabdocarpus tunicatus ,berger is a species founded on a specimen from the ,coal ,measures of ,silesia characterised by an outer carbonised testa prolonged apically as a blunt snout and1 as seen in fig4 #ejf1 ,k1 covering an apparently ribbed nucule1 but the #8ribs' are due to the presence of fibrous strands and are not ribs in the ordinary sense4 ,the outer tissue shows numerous longitudinal striations due presumably to the presence of fibrous elements in the sarcotesta like those shown in the petrified seed represented in fig4 #eja1 ,c4 ,the genus is defined by ,berger as follows3 #8,semina ovata vel elliptico-oblonga secundum longitudinem parallele nervosa vel tenuissime striata1 putamine 7interdum deficiente7 instructa4' ,as used by ,berger and many other authors ,rhabdocarpus includes a miscellaneous collection of seeds often differing widely from the type-species4 ,many of the examples correctly referred to ,berger's genus are platyspermic though a bilateral symmetry is by no means always clear4 ,renault and ,zeiller#idi in their definition of ,rhabdocarpus include bilateral symmetry as a characteristic feature and speak of the seeds as oblong or oval with a pointed or truncate apex and a rounded base4 ,impressions of ,rhabdocarpus differ from those of ,cardiocarpus or ,cordaicarpus in their more elongate form1 always longer than broad1 and in the absence of a basal sinus4 ,the seeds found attached to ,neuropteris pinnae and1 in external features1 agreeing with many specimens included in ,berger's genus1 have been transferred by ,p4 ,bertrand#iej and ,arber#iea to a new genus ,neurospermum#ieb4 ,arber#iec in his recent revision of ,british seeds proposes to restrict the name ,rhabdocarpus to platyspermic seeds having a #8large unsymmetrical nucule enclosed in a large unsymmetrical wing or sarcotesta1' that is to forms symmetrical in one plane4 ,in this category he includes ,rhabdocarpus tunicatus ,berg4 7fig4 #ejf1 ,k7 and ,r4 subtunicatus#ied ,grand',eury1 but it is not clear on what grounds ,berger's species is spoken of as symmetrical in only one plane3 in the species ,r4 ,lilleanus ,arb4#iee the symmetry is hardly sufficiently well defined to rank as a generic character4 ,in the case of the ,neuropteris seeds the apical snout is slightly curved1 thus giving them an unsymmetrical appearance 7cf4 fig4 #dbb1 p4 #aad74 ,the ,carboniferous and ,permian seeds usually referred to ,rhabdocarpus are transferred by ,arber to his genus ,platyspermum#ief1 a designation for which it is proposed to substitute ,nathorst's genus ,holcospermum#ieg4 ,in seeds preserved as more or less flattened impressions it is practically impossible in many cases accurately to determine the symmetry3 as fig4 #ejf1 ,a1 shows1 casts indistinguishable from some examples of ,platyspermum are radially symmetrical4 ,brongniart#ieh extended the original definition of ,rhabdocarpus to include certain anatomical characters1 and these have been more fully defined by ,bertrand#iei4 ,it is for seeds showing these anatomical features that the name ,rhabdospermum is now proposed4 ,this course is followed on the ground that it is advisable to avoid confusion between petrified specimens and impressions which in spite of superficial resemblance may not be closely related4 ,in some cases it is practically certain that an impression of the ,rhabdocarpus type is generically identical with a seed of similar form showing the anatomical structure of ,rhabdospermum1 but unless identity is established a distinct terminology is preferable4 ,the use of the generic name ,rhabdospermum carries with it an implication of platyspermy1 but under ,rhabdocarpus may be included seeds which are radiospermic and platyspermic4 ,some seeds agreeing with ,rhabdospermum are referred by ,grand',eury#ifj to ,poroxylon1 and it is probable that ,rhabdospermum like ,cardiocarpus is a ,cordaitean seed4 ,on the other hand ,rhabdocarpus may well include species1 apart from those transferred to ,neurospermum1 that belong to ,pteridosperms4 ,a species1 ,rhabdocarpus ,oliveri1 recently described by ,kidston#ifa from the ,staffordshire coalfield is an example of a radiospermic seed which may be assigned to a ,pteridosperm4 ,the type-specimen is an ovate seed #d cm4 long and #b cm4 broad agreeing in form and surface-features with ,rhabdocarpus as already defined1 but the evidence it affords of internal structure is insufficient to determine its position with regard to genera founded on anatomical characters4 ,other examples of ,rhabdocarpus are described by ,lesquereux#ifb and ,white#ifc from ,american ,coal ,measures1 by ,grand',eury#ifd from the ,loire1 by ,renault#ife from ,autun1 and by many other authors4 ,rhabdospermum4 ,gen4 nov4 ,the platyspermic seeds included in this genus agree in size and form with impressions assigned to ,rhabdocarpus and as regards the main features conform anatomically to ,cardiocarpus2 they were probably borne on ,cordaitean plants4 ,fig4 #eja1 ,c1 represents a longitudinal section of the species ,rhabdospermum cyclocaryon described by ,brongniart as ,rhabdocarpus cyclocaryon3 the sarcotesta is particularly well developed in the apical region2 at the apex a portion of the micropyle is seen at m and near the nucellus are pieces of the sclerotesta shown in black4 ,the presence of anastomosing fibres near the surface is a characteristic feature3 these1 as ,bertrand points out1 do not form a hypodermal tissue in the strict sense as they may be separated by some of the thin-walled parenchyma of the sarcotesta from the epidermis4 ,the sclerotesta is only partially preserved but the inner portion forms a dark line enclosing the nucellus1 the superficial tissue of which is separated from the shrunken prothallus represented by the almost spherical dotted region3 the remains of an archegonium are seen at a 7fig4 #eja1 ,c7 and the characteristic tent-pole apex of the prothallus is shown at b4 ,while in shape and in the general plan of organisation ,rhabdospermum agrees with ,cardiocarpus1 the vascular system in the chalazal region constitutes a distinguishing feature4 ,in ,rhabdospermum the main vascular strand passes through the sclerotesta1 e1 e1 fig4 #eja1 ,e1 before giving off two bundles which bend back 7#8faisceaux rcurrents'71 traverse the shell1 and then pass up the sarcotesta in correspondence with the feebly developed lateral keels as far as the micropyle1 while in ,cardiocarpus 7fig4 #ejj1 ,b7 the bundles are given off before the main strand reaches the sclerotesta4 ,similar recurrent bundles occur also in ,mitrospermum 7fig4 #did1 ,k7#ifg4 ,mitrospermum4 ,a4 ,arber4 ,mitrospermum compressum 7,williamson74 ,mrs ,arber#ifh proposed the name ,mitrospermum#ifi1 suggested by the peculiar form of the seed-base1 as a substitute for ,cardiocarpon for ,williamson's species ,c4 compressum#igj from the ,lower ,coal ,measures of ,lancashire4 ,the seed is platyspermic and there is some evidence that it split into two valves along the principal plane 7the longer axis of the section1 fig4 #did1 ,l74 ,the diagrammatic and partially restored longitudinal section reproduced in fig4 #did1 ,k1 shows the main features3 a sarcotesta1 sa1 covers the surface of the testa as a thin layer except at the edges of the flattened sides where it forms a wing-like border2 preserved as an impression the seed would be assigned to ,samaropsis4 ,the sclerotesta1 sc1 has a pointed apex which surrounds the lower third of the micropyle and a broad base perforated by the chalazal vascular strand4 ,there was probably a narrow inner flesh as in ,trigonocarpus and recent ,cycadean seeds 7fig4 #did1 ,k1 cf74 ,the nucellus was free from the integument except at the base1 as in ,trigonocarpus and ,stephanospermum 7fig4 #did1 ,k1 n73 internal to the shrivelled remains of the inner flesh there was a nucellar tapetum surrounding the megaspore4 ,details as to the pollen-chamber are lacking though there are indications that it resembled that of some species of ,cordaitean seeds4 ,the main vascular supply passes through the sclerotesta and then forms a low cushion of short reticulate elements below the base of the nucellus from which two bundles are given off 7fig4 #did1 ,k1 v7 in the principal plane4 ,the course of the bundles which pierce the sclerotesta led ,mrs ,arber to remove this seed from ,cardiocarpus1 as recently defined by ,bertrand#iga1 since in that genus the integumental bundles have their origin below the sclerotesta4 ,in the course of the vascular bundles ,mitrospermum is intermediate between ,rhabdospermum and ,taxospermum4 ,this genus is founded on a detached seed1 but its resemblance to undoubted ,cordaitean species favours its attribution to that group though1 as ,mrs ,arber points out1 some markedly platyspermic seeds are known to have been borne on fern-like fronds and ,mitrospermum may belong to some genus of ,pteridosperms4 ,diplotesta4 ,brongniart4 ,diplotesta ,grand',euryana ,brongniart4 ,the generic name ,diplotesta1 suggested by ,grand',eury1 was given by ,brongniart#igb to a ,grand' ,croix seed which he compared with that of the ,conifer ,cephalotaxus4 ,the type-specimen is elliptical and platyspermic 7fig4 #die1 ,h1 p4 #cbb71 and differs from ,taxospermum in the cordate form of the seed-cavity1 also in the more restricted union of nucellus and testa4 ,the testa is differentiated into a sarcotesta 7sa7 and sclerotesta1 and the latter forms two feebly developed keels in the principal plane3 a characteristic feature shared with ,mitrospermum is the splitting of the shell into two equal valves 7fig4 #die1 ,f74 ,fig4 #die1 ,h1 shows the contracted cylindrical nucellus and the pollen-chamber3 the sarcotesta 7sa7 is only partially preserved4 ,diplotesta differs from ,cardiocarpus in the course of the integumental vascular bundles which are of the type illustrated by ,rhabdospermum1 ,taxospermum1 and ,cyclocarpus1 but from these genera it is distinguished by the dehiscence of the shell1 also by its form and certain anatomical features as described by ,brongniart and ,bertrand#igc4 ,in this genus ,bertrand includes ,brongniart's species ,sarcotaxus avellana 7fig4 #die1 ,f71 a correlation suggested by the latter author4 ,leptocaryon4 ,brongniart4 ,brongniart#igd founded this genus for a single species1 ,leptocaryon avellana1 represented by a ,grand' ,croix specimen #ab #aj mm41 which he believed to be related to ,taxus4 ,leptocaryon differs from ,taxospermum in the structure of the testa1 but resembles it in external features4 ,bertrand#ige in his revision and extension of ,brongniart's account says that the sections throw no light on the nature of the vascular supply1 and it is therefore impossible to form a satisfactory opinion as to the relationships of the genus4 ,renault#igf referred this genus to the ,cordaitales1 but we have no evidence as to the parent-plant4 ,taxospermum4 ,brongniart4 ,brongniart#igg gave this name to a small elliptical seed1 #aei mm41 recalling in external features the seed of ,taxus1 a genus to which he believed the ,grand' ,croix species to be related4 ,the type-species ,taxospermum ,grneri 7fig4 #die1 ,g7 has a comparatively thin testa characterised by the absence of a sub-chalazal pad formed by the swelling of the sclerotesta4 ,the nucellus is attached by a broad base to the testa and the two regions appear to be connected for a short distance on the flanks#igh2 in this feature the seed is comparable with that of the ,conifer ,torreya and differs from the other platysperms1 ,diplotesta1 ,rhabdospermum1 etc4 ,bertrand#igi states that the main vascular strand extends from the hilum to the chalaza before giving off the two opposite bundles which #8follow the floor of the shell-cavity1 and on reaching the flanks traverse the shell obliquely from below upwards#ihj4' ,in the course and position of the integumental bundles ,taxospermum differs from ,cardiocarpus1 ,cycadinocarpus1 and ,rhabdospermum4 ,in this genus ,bertrand includes ,sarcotaxus angulosus ,brongn4 and ,s4 olivaeformis ,brongn4#iha ,compsotesta4 ,bertrand ex ,brongniart ,,ms4 ,compsotesta ,brongniarti ,bertrand4 ,the generic name ,compsotesta#ihb1 though adopted by ,brongniart for some incomplete specimens from ,grand' ,croix1 was not published either by him or ,renault3 it has recently been revived by ,bertrand#ihc in his account of the anatomical details of ,brongniart's sections4 ,this seed appears to be closely allied to the polypterous forms ,ptychotesta and ,hexapterospermum3 the testa consists of a sarcotesta differentiated into two zones the outer of which contains vascular bundles in correspondence with the ribs1 and an inner shell4 ,there is a nucellar vascular supply and the nucellus is free on the flanks as in ,stephanospermum and ,trigonocarpus4 ,samaropsis4 ,goeppert4 ,the characters of this ,permian and ,carboniferous genus have already been described3 the name has reference only to superficial features especially the samara-like #8wing1' and connotes no special anatomical features4 ,samaropsis fluitans 7,dawson74 ,the species described by ,dawson#ihd as ,cardiocarpum fluitans from ,carboniferous strata in ,nova ,scotia1 is represented by oval seeds with a fairly broad border usually showing an apical notch4 ,fig4 #ejb1 ,a1 is a copy of ,dawson's figure3 the apparent absence of an apical sinus in the #8wing' is probably due either to an error in interpretation or to some imperfection in the specimen4 ,as fig4 #ejb1 ,a1 shows1 the type-specimens are far from satisfactory1 and it may be that they are not specifically identical with the more complete specimens from ,european strata referred to ,dawson's species4 ,zeiller#ihe points out that seeds of this species vary considerably in size1 but there is always in well-preserved examples a bifid beak at the apex4 ,seeds of similar form though not specifically identical are described from the ,coal ,measures of ,missouri as ,cardiocarpon 7,samaropsis7 ,branneri ,fairch4 and ,white#ihf4 ,good examples of ,s4 fluitans are figured by ,weiss#ihg from the ,coal ,measures of ,saarbrcken and the species is widely distributed in ,upper ,carboniferous beds generally4 ,samaropsis bicaudata ,kidston4 ,this species 7fig4 #ejb1 ,e7 originally described#ihh from ,lower ,carboniferous rocks in ,scotland as ,cardiocarpus bicaudata and subsequently assigned to ,samaropsis1 is characterised by a greater development of the flat wing-like border which is divided into two long tapering basal lobes4 ,seeds of similar form are figured by ,lesquereux#ihi from ,pennsylvania as ,cardiocarpus 7,ptilocarpus7 bicornutus4 ,samaropsis 7,samarospermum7 moravica 7,helmhacher74 ,this type#iij 7fig4 #ejb1 ,h7 is characterised by the great length of the wing-like border and on that account it was transferred by ,arber to a new genus4 ,it was originally described by ,helmhacher from the ,permian of ,moravia as ,jordania moravica and the type-specimen has been refigured by ,zeiller#iia who records the species from ,upper ,carboniferous and ,permian rocks in ,france3 it is recorded also from several localities in ,germany#iib4 ,seeds figured by ,potoni#iic from the ,permian of ,thuringia as ,samaropsis ,crampii 7,hartt7 are undoubtedly examples of ,s4 moravica3 the true ,s4 ,crampii has recently been well illustrated by ,dr ,stopes#iid from the ,westphalian of ,new ,brunswick4 ,the species is recorded by ,arber#iie from the ,kent coalfield4 ,samaropsis emarginata 7,goeppert and ,barger74 ,the seed represented in fig4 #ejb1 ,b1 from the ,lower ,coal ,measures of ,kilmarnock1 ,scotland#iif1 affords a good example of the genus3 the species was originally described by ,berger as ,cardiocarpon emarginatum and it was on this type that ,fiedler founded the genus ,cyclocarpon#iig4 ,it has been referred by many authors to ,cardiocarpon and might be regarded as a type intermediate between ,cordaicarpus1 as used in this chapter1 and ,samaropsis1 though the breadth of the border is more in keeping with the latter designation4 ,the figured specimen is #af cm4 long and #ad cm4 broad2 the nucule has a slightly cordate base and shows several faint converging ribs which are too inconspicuous to be represented in a natural-size drawing4 ,a narrow median groove in the apical region shows the position of a vascular strand4 ,the species is recorded from several countries3 similar though specifically distinct seeds1 described by ,dawson as ,cardiocarpon cornutum1 have recently been re-described by ,dr ,stopes#iih from the ,westphalian of ,new ,brunswick where they occur in association with the leaves of ,cordaites ,robbii ,daws4 ,illustration3 ,fig4 #ejb4 ,a1 ,samaropsis fluitans4 ,b1 ,samaropsis emarginata4 ,c1 ,d1 ,cordaicarpus ,cordai4 ,e1 ,samaropsis bicaudata4 ,f1 ,samaropsis ,seixasi4 ,g1 ,samaropsis barcellosa4 ,h1 ,samaropsis moravica4 ,i1 ,samaropsis bignonioides4 ,k1 ,samaropsis ,newberryi4 7,a1 after ,dawson2 ,b1 ,r4 ,k4 #aegf2 ,c1 ,r4 ,k4 #ahii2 ,d1 ,r4 ,k4 #dfdg2 ,e1 after ,kidston2 ,f1 ,g1 after ,white2 ,h1 after ,zeiller2 ,i1 after ,fiedler2 ,k1 ,r4 ,k4 #bcac4 ,all nat4 size47 ,samaropsis ,newberryi ,andrews4 ,this species was originally described by ,andrews#iii from the ,coal ,measures of ,ohio3 the specimen shown in fig4 #ejb1 ,k1 was sent to ,dr ,kidston by ,mr ,claypole4 ,the whole seed is #e cm4 wide and #ce cm4 in depth2 it is characterised by a short and relatively broad nucule surrounded by a very broad and flat border showing faintly marked radially disposed lines and in places some irregularly distributed pits4 ,the apex is emarginate and there is a broad and deep sinus in the sarcotesta in the chalazal region4 ,the seed resembles ,samaropsis alata ,kidst4#ajjj and ,s4 ,baileyi 7,daws47#ajja but it differs from these in the greater breadth of the #8wing' and in the form of the nucule4 ,the seed described by ,fiedler#ajjb as ,jordania bignonioides 7fig4 #ejb1 ,i7 agrees closely with ,s4 alata ,kidst4 but is probably specifically distinct4 ,samaropsis barcellosa 7,white74 ,white#ajjc described this species 7fig4 #ejb1 ,g7 from ,permo-,carboniferous rocks in ,brazil 7,rio ,grande do ,sul7 as ,cardiocarpon barcellosum4 ,the nucule is said to be cordate but1 as seen in the figure1 there is no clear indication of a basal sinus3 the presence of a relatively broad #8wing1' as ,white says1 entitles the seed #8to a place in the ,samaropsis section of the genus4' ,the author of the species compares it with seeds described from ,westphalian rocks in ,ohio#ajjd and ,pennsylvania#ajje4 ,it is interesting to find a type which is common in both ,europe and ,north ,america in the western portion of ,gondwana ,land4 ,seeds of similar form are recorded also from ,india1 ,south ,africa1 and ,australia#ajjf4 ,samaropsis ,seixasi 7,white74 ,this ,brazilian species from the same beds is described by ,white as ,gangamopteris 7,samaropsis7 ,seixasi#ajjg3 it is characterised by a small ovate nucule #h-aj mm4 long and #e mm4 broad1 in some specimens surrounded by a complete #8wing' extending above the apex and below the base1 giving the seed an appearance similar to that of ,samaropsis 7,samarospermum7 moravica while sometimes1 as in the example shown in fig4 #ejb1 ,f1 the broad border is preserved only at the sides4 ,these seeds are abundant in the ,santa ,catharina beds1 where they were discovered by ,dr ,esdras do ,prado ,seixas1 in association with leaves of ,gangamopteris1 and ,white thinks that they were borne on the fertile leaves of that genus which he has named ,arberia#ajjh4 ,although there is as yet no proof of a connexion between ,gangamopteris and seeds of this or any other type it is almost certain that it was a seed-producing plant4 ,samaropsis ,leslii sp4 nov4 ,illustration3 ,fig4 #ejc4 ,samaropsis ,leslii4 ,from ,vereeniging1 ,s4 ,africa4 7,mr ,leslie's ,collection2 nat4 size47 ,the seed on which this species is founded was discovered by ,mr ,t4 ,n4 ,leslie in the ,ecca beds 7,permo-,carboniferous7 of ,vereeniging1 ,south ,africa1 a locality from which the same geologist has obtained leaves of ,cordaites1 ,psygmophyllum1 ,glossopteris and other genera#ajji4 ,in the slightly cordate base and tapered apex 7fig4 #ejc7 the nucule agrees closely with those of ,european examples1 but the ,vereeniging type is distinguished by its larger dimensions and by the wider border indicating a thick sarcotesta continued basally into a stout stalk4 ,the apex is emarginate and a median rib marks the position of a vascular strand4 ,there is no evidence as to the nature of the parent-plant4 ,samaropsis indica 7,zeiller74 ,prof4 ,zeiller#ajaj described this species as ,cardiocarpus indicus from the ,karharbari 7,lower ,gondwana7 beds of ,india4 ,an examination of the type-specimens enables me to confirm the accuracy of the original account4 ,the platyspermic seed is #ee cm4 long and #de cm4 broad2 a cordate nucule is enclosed by a flat border similar to that of ,samaropsis ,leslii but narrower especially on the sides of the nucule4 ,at the apex there is a deep sinus extending to the nucule1 and at the base a fairly broad band of carbonaceous matter shows the position of the chalazal vascular strand4 ,the seed is characterised by its large size and by its almost orbicular form3 it occurs as a detached specimen in beds containing ,cordaites 7,noeggerathiopsis7 and ,glossopteris4 ,a species from ,arkansas described by ,lesquereux#ajaa as ,cardiocarpus ingens ,cordaicarpus ingens 7,lesq47 affords another example of a large seed similar to ,c4 indicus and1 except in its more orbicular form1 to ,samaropsis ,leslii4 ,samaropsis ,milleri 7,feistmantel74 ,illustration3 ,fig4 #ejd4 ,samaropsis ,milleri4 7,indian ,geological ,survey1 ,calcutta2 nat4 size47 ,an examination of the type-specimen from the ,calcutta ,museum enables me to amplify the original description in an important particular4 ,the species was found in ,lower ,gondwana 7,katharbari7 beds in ,india and referred by ,feistmantel#ajab to the genus ,carpolithes4 ,arber#ajac1 who tentatively employed the generic name ,cardiocarpus in place of ,carpolithes1 suggests that the seeds may be radiospermic1 as ,feistmantel's drawings show only a very narrow border to the nucule4 ,the specimen reproduced in fig4 #ejd was figured by ,feistmantel without any indication of a definite sarcotesta or wing1 but as seen in the drawing the ovate cordate sclerotesta is surrounded on one side and at the base by an outer envelope3 this is clearly seen at the apex where it shows a rounded termination sloping downwards towards the micropyle precisely as in ,samaropsis indica 7,zeill474 ,the border is narrow at the sides and broader at the base as in ,s4 ,leslii4 ,the seed is #de cm4 long and #bc cm4 broad1 differing from ,s4 indica in its rather smaller size and in the slightly narrower nucule4 ,though there is no decisive evidence as to the parent-plant the occurrence of a specimen of this species partially covered by a scale-leaf of a type#ajad very similar to that which is generally recognised as belonging to ,glossopteris suggests the possibility that the seeds may belong to that genus4 ,scale-leaves of ,glossopteris are described in ,volume ii41 but it may be added here that leaves similar in form to those from ,india1 ,australia1 and elsewhere are figured by ,geinitz#ajae from the ,altai ,mountains as ,trigonocarpus8 actaeonelloides3 the specimens are represented with the basal scar at the apex4 ,cordaicarpus4 ,geinitz4 ,in view of the fact that the generic names ,cardiocarpus1 ,cordaicarpus1 and other designations have been applied to casts and impressions which cannot be distinguished by any constant or important feature it is proposed to adopt the name ,cordaicarpus for platyspermic seeds1 preserved as casts or impressions1 having a comparatively narrow border enclosing an ovate or cordate-ovate nucule2 the base is either rounded or cordate4 ,the choice between ,cordaicarpus and ,samaropsis depends on the breadth of the border4 ,cordaicarpus1 though more suggestive of a ,cordaitean alliance1 may in some cases be a ,pteridosperm seed4 ,cordaicarpus ,cordai 7,geinitz74 ,lenticular seeds more or less orbicular or broadly ovate 7fig4 #ejb1 ,c1 ,d71 often slightly cordate at the base of the nucule and with a broadly acute apex3 the border is narrow or sometimes hardly represented as in the seeds described by ,berger as ,rhabdocarpus ovoides1 a species similar to but more oval than ,cordaicarpus ,cordai4 ,the latter species#ajaf occurs in several coalfields in ,britain1 ,france1 ,germany1 and elsewhere4 ,fig4 #ejb1 ,c1 shows a good example from the ,middle ,coal ,measures of ,yorkshire1 #i mm4 long by #h mm4 broad2 on the very slightly cordate nucule are several faint ribs converging towards the base and apex and between them fine striations1 characters too indistinct to be reproduced in the natural-size drawing4 ,the flat border represents the sclerotesta4 ,the seed shown in fig4 #ejb1 ,d1 from the ,westphalian series of ,warwickshire belongs to the same species or is a closely allied type3 the faint suggestion of reticulation on its surface might be regarded as a reason for referring it to ,c4 areolatus ,boul4#ajag1 a form characterised by a reticulation on the testa1 described by ,zeiller#ajah and other authors4 ,this reticulation is1 however1 in some cases at least1 formed by crumpling and splitting of the superficial carbonised film into more or less regular meshes3 the figured specimen occurs with several other seeds of the same type1 most of which have a smooth surface4 ,dr ,kidston tells me that a recent critical examination of seeds in his collection leads him to regard some specimens 7e4g4 fig4 #ejb1 ,d7 previously referred by him to ,c4 ,cordai as identical with ,carpolithes membranaceus ,goepp4#ajai ,illustration3 ,fig4 #eje4 ,cordaicarpus ,cordai4 ,cuticle of the testa4 7,kidston ,collection47 ,the photograph reproduced in fig4 #eje shows the result of chemically treating the carbonised cuticle of a seed of ,cordaicarpus ,cordai1 a method little used as yet in the case of ,palaeozoic plants but which may be useful in distinguishing seeds which cannot be satisfactorily separated by microscopic features4 ,the superficial cells have very thick walls and present an appearance similar to that of the sclerous cells in the testas of some petrified specimens4 ,the larger seed shown in fig4 #eja1 ,d1 from ,commentry1 described by ,renault and ,zeiller#ajbj as ,cardiocarpus sclerotesta1 is another example of ,cordaicarpus as now defined4 ,,iv4 ,miscellaneous ,seeds4 ,in this section are included genera based on characters of comparatively little morphological importance2 their claim to treatment under a common heading is that we know little or nothing of their anatomical features or of the parent-plants4 i4 ,ribbed seeds4 ,the seeds represented by the following genera possess ribs or flanges usually in multiples of three2 the transverse section may be triangular1 hexagonal1 or polygonal4 ,the symmetry is generally radial1 but it is difficult to determine whether a slight departure from the radiospermic form is an original feature or the result of pressure4 ,some of the ribbed seeds with which we are now concerned are no doubt closely allied to ,trigonocarpus and should be included in the ,trigonocarpales1 but others may well be distinct forms4 ,genera3 ,hexagonocarpus1 ,decagonocarpus1 ,polypterocarpus1 ,rhynchogonium1 ,boroviczia1 ,diplopterotesta1 ,musocarpus1 ,holcospermum4 ,hexagonocarpus4 ,renault4 ,this generic name is adopted by ,renault#ajba for casts from ,commentry which1 while probably identical with ,brongniart's ,hexapterospermum1 afford no confirmatory anatomical evidence4 ,the species ,hexagonocarpus crassus#ajbb is represented by casts or nucules characterised by six well-defined ribs and grooves with a length of nearly #c cm4 ,in this genus may be included the cast from the ,coal ,measures of ,lancashire described by ,williamson#ajbc as ,hexapterospermum ,noeggerathi 7fig4 #ejf1 ,h71 and another ,british example is afforded by ,hexagonocarpus ,hookeri ,kidst4#ajbd1 a rare fossil in the ,south ,staffordshire coalfield4 ,it is impossible confidently to assign these ribbed casts to genera founded on petrified specimens as they almost certainly belong to different types1 but the employment of the name ,hexagonocarpus may conveniently be used for casts or impressions of seeds with six longitudinal ribs differing in their relatively broader and less prominent form from the wing-like flanges of ,polypterocarpus 7cf4 fig4 #dif1 ,b74 ,the seeds described by ,dr ,p4 ,bertrand#ajbe as ,hexapterospermum modestae1 and believed by him to belong to a plant with ,neuropteris fronds1 should be included in ,hexagonocarpus as we have no definite knowledge of their anatomical features4 ,decagonocarpus4 ,renault4 ,this name1 proposed by ,renault#ajbf1 is applied to seeds without petrified tissues characterised by ten ribs2 an example is afforded by ,decagonocarpus olivaeformis from the ,commentry coalfield1 an elliptical seed which bears a close resemblance to ,holcospermum sulcatum 7fig4 #ejf1 ,a7 except in the smaller number of ribs4 ,polypterocarpus4 ,grand',eury4 ,grand',eury#ajbg adopted this generic name for seeds from ,st tienne characterised by the presence of three1 six1 or more deep wings or flanges4 ,the term ,pterospermum has recently been proposed by ,arber#ajbh for a seed from the ,coal ,measures of ,staffordshire1 which he names ,p4 anglicum3 the type-species of the genus has three deep wings1 one from each angle4 ,for the same seed ,kidston#ajbi proposed the name ,tripterospermum ellipticum1 but as ,arber's account was published first his specific name has priority4 ,pterospermum had1 however1 been previously used for a genus of ,sterculiaceae1 and partly on this account but mainly because ,grand',eury's genus ,polypterocarpus is available the latter designation is adopted4 ,in ,polypterocarpus anglicus 7fig4 #dif1 ,b7 the flanges project slightly beyond the apex of the seed and there is a small notch at the base2 the nucule is #e cm4 long and #a cm4 broad4 ,while it is not improbable that this seed is generically identical with ,brongniart's ,tripterospermum#ajcj1 it is safer1 in the absence of structural details1 to employ the less committal term4 ,there is no information with regard to the nature of the parent-plants of species of ,polypterocarpus4 ,the ,english seed from the ,middle ,coal ,measures of ,derbyshire and the ,staffordshire coalfield described by ,arber#ajca as ,radiospermum ornatum and by ,kidston#ajcb as ,polypterospermum ornatum affords another example of ,polypterocarpus as the generic name is here employed4 ,rhynchogonium4 ,heer4 ,heer#ajcc proposed this generic name for some globose1 ovate1 or oblong #8fruits' from ,lower ,carboniferous strata in ,spitzbergen1 including also fragments of #8leaves' which without satisfactory evidence he believed to belong to the same plant4 ,the supposed fruits are clearly seeds1 and ,nathorst regards the #8leaves' as portions of a ,fern rachis4 ,heer described four species1 but these have since been reduced to two1 and indeed it is probable that only one type1 ,rhynchogonium costatum1 is represented4 ,nathorst#ajcd compares ,heer's seeds with a ,lower ,carboniferous species described by ,young#ajce as ,trigonocarpum gloagianum1 the resemblance of which to the ,spitzbergen seeds was pointed out by ,kidston4 ,a seed of ,rhynchogonium costatum is about the size of a hazel-nut and may reach a length of #ba mm42 it is ovate1 with a broad rounded base1 and in the upper third is tapered and conical1 the sides of the characteristic snout being distinguished from the smooth surface of the rest of the seed by the presence of eight ribs converging towards the apex 7#ejf1 ,g74 ,zalessky#ajcf recorded closely allied seeds from ,lower ,carboniferous beds in ,northern ,russia1 assigning them to a new genus ,boroviczia1 the type-species being ,b4 ,karpinskii2 he adduced arguments in favour of ,heer's interpretation of the fossils as fruits but1 according to ,nathorst1 this view has been abandoned4 ,in his recent memoir on the ,culm flora of ,spitzbergen ,nathorst#ajcg discusses the morphological nature of ,rhynchogonium seeds and describes additional specimens4 ,without the aid of petrified examples it is hardly possible to determine the true nature of the fossils4 ,illustration3 ,fig4 #ejf4 ,a1 ,holcospermum sulcatum4 ,b1 ,c1 ,codonospermum anomalum4 ,d1 ,diplopterotesta spitzbergensis 7 #c74 ,e1 ,gnetopsis elliptica 7cupule74 ,f1 ,thysanotesta sagittula4 ,g1 ,rhynchogonium costatum4 ,h1 ,hexagonocarpus ,noeggerathi4 ,i1 ,boroviczia ,karpinskii4 ,k1 ,rhabdospermum tunicatum4 7,a1 ,kidston ,collection2 ,b1 after ,grand',eury2 ,c1 after ,renault and ,zeiller2 ,d1 ,f1 ,g1 after ,nathorst2 ,e1 after ,renault2 ,h1 after ,williamson2 ,i1 after ,zalessky2 ,k1 after ,berger47 ,some specimens of ,rhynchogonium sulcatum in ,dr ,kidston's collection show the original surface-features3 the carbonised integument is divided in the upper region into linear lobes separated from one another at their origin by fairly wide sinuses1 a type of integument suggesting comparison with ,physostoma4 ,this species was originally described by ,lindley and ,hutton as ,carpolithes sulcata#ajch from ,lower ,carboniferous rocks at ,newhaven in ,scotland and has recently been figured by ,zalessky#ajci from specimens in the ,kidston collection from the ,lower ,calciferous sandstone of ,midlothian4 ,nothing definite can be said as to the parent-plant1 but it is significant that in ,midlothian ,rhynchogonium sulcatum occurs in a bed full of isolated pinnules of a ,cardiopteris almost to the exclusion of any other fossils#ajdj4 ,the seed figured by ,nathorst#ajda from the ,culm of ,spitzbergen as ,lagenospermum8 glandiforme agrees closely with ,rhynchogonium and ,boroviczia1 and it is impossible to decide whether the lobed appearance is due to the presence of a cupule or to the divisions of an integument4 ,boroviczia4 ,zalessky4 ,the specimens from ,lower ,carboniferous beds in ,russia#ajdb on which this genus was founded are perhaps unnecessarily separated from ,rhynchogonium2 they are ovate and beaked1 #aj mm4 long with a maximum breadth of #f mm4 ,the type-species1 ,boroviczia ,karpinskii 7fig4 #ejf1 ,i71 is represented both by specimens in which the cast is complete and by others in which the apical snout of the integument is split into separate lobes identical in form and apparently in number with those of ,rhynchogonium4 ,nathorst#ajdc1 who retains the generic name and describes two additional species from ,spitzbergen1 points out that in ,boroviczia the tapered apex is more sharply differentiated from the broader basal portion1 a difference hardly worthy of generic recognition4 ,if ,boroviczia is retained as a genus distinct from ,rhynchogonium it should include the seeds described by ,young as ,trigonocarpum gloagianum4 ,diplopterotesta4 ,nathorst4 ,diplopterotesta spitzbergensis 7,heer74 ,heer#ajdd included in ,samaropsis some seeds1 described as ,samaropsis spitzbergensis1 from ,lower ,carboniferous strata in ,spitzbergen which differ considerably from typical examples of the genus4 ,these have recently been made the type of a new genus ,diplopterotesta#ajde3 they are platyspermic seeds nearly twice as long as broad1 #f-i #ce-e mm41 characterised by a thin sclerotesta expanded throughout the length of the seed into two prominent transversely striated wing-like ribs or flanges 7fig4 #ejf1 ,d74 ,at the apex1 which is broad in contrast to the pointed basal end of the seed1 the sclerotesta forms a crown of eight lobes about the flat summit of the seed-body4 ,as ,nathorst points out1 this species closely resembles the ,carboniferous seeds figured by ,grand',eury#ajdf as ,polypterocarpus1 but in the latter type there are more than two wings4 ,nathorst's figures1 one of which is reproduced in fig4 #ejf1 ,d1 suggest a difficulty in determining the number of the flanges1 which would seem to be more than two1 but this appearance is regarded by ,nathorst as misleading and he believes that except at the apex there are only two wings4 ,musocarpus4 ,brongniart4 ,brongniart#ajdg proposed this name for two species1 ,m4 prismaticus and ,m4 difformis1 from ,french ,coal ,measures1 but gave no description of the specimens4 ,the type-species1 described from the ,loire by ,grand',eury as ,musocarpus prismaticus#ajdh1 is an ovate seed nearly #c cm4 long with six longitudinal ribs1 three being more prominent than the others1 and characterised by a ribbed prolongation of the base of uniform diameter spoken of as a carpophore1 which was apparently articulated to the lower part of the seed-proper from which it was easily detached by a natural absciss-layer4 ,nothing is known of the structure or of the affinity of the genus4 ,some specimens in ,dr ,kidston's collection from ,westphalian beds in ,lanarkshire are closely allied to or perhaps identical with ,m4 prismaticus4 ,in the presence of a distinct basal region ,musocarpus resembles ,codonospermum#ajdi1 though without any knowledge of the anatomy of the former type it is impossible to say whether or not this resemblance has any morphological importance4 ,holcospermum4 ,nathorst4 ,holcospermum sulcatum 7,sternberg74 ,the cast reproduced in fig4 #ejf1 ,a1 affords a good example of a form of seed recorded under several generic names and not uncommon in ,upper ,palaeozoic rocks in ,europe and ,north ,america1 which in most cases cannot be assigned to a genus implying the possession of certain anatomical characters4 ,this type was figured by ,sternberg#ajej from the ,coal ,measures of ,radnitz as ,carpolites sulcatus4 ,some #8fruits' collected on the beach near ,newhaven1 ,midlothian1 from the ,calciferous ,sandstone series1 are figured by ,lindley and ,hutton#ajea as ,carpolithes sulcata1 but as already stated these have been transferred#ajeb to the genus ,rhynchogonium4 ,several authors have referred specimens of the type now included in ,holcospermum to ,rhabdocarpus1 but that genus1 as stated on a previous page1 is restricted to seeds agreeing in form with ,r4 tunicatus4 ,renault#ajec instituted the genus ,colpospermum for a partially petrified seed from ,commentry agreeing externally with ,carpolites sulcatus ,sternb4 and regarded by him as specifically identical1 characterised by longitudinal ribs which represent folds of the testa1 the intervening grooves being occupied by an irregular reticulum formed by occasionally anastomosing smaller ribs4 ,the generic name ,colpospermum should therefore be reserved for ribbed seeds showing the anatomical features described by ,renault and ,zeiller3 its application to ,sternberg's species is inadvisable on the ground that we have no information with regard to the morphological nature of the ribbing4 ,more recently ,arber#ajed has proposed the name ,platyspermum1 a name previously applied to a ,cruciferous plant1 for ,stephanian and ,permian seeds formerly assigned to ,berger's genus ,rhabdocarpus1 which are symmetrical in two planes4 ,in this genus he includes ,platyspermum sulcatum and among other species ,p4 ,kidstoni founded on a seed originally identified by ,kidston#ajee as ,rhabdocarpus multistriatus ,sternb4 which1 though probably a distinct species1 is of the same general type as ,c4 sulcatus ,sternb4 ,the cast represented in fig4 #ejf1 ,a1 from the ,middle ,coal ,measures of ,yorkshire is #ce cm4 long and has #ah regular longitudinal ribs3 it is radially symmetrical and does not conform in this respect to ,arber's definition of ,platyspermum4 ,in many cases1 e4g4 the flattened seed figured by ,kidston as ,rhabdocarpus multistriatus1 it is impossible to determine the symmetry of the seed4 ,the old generic name ,carpolites1 ,carpolithes or ,carpolithus has been used in a very wide sense and does not connote any well-defined features2 it should be reserved1 in the form ,carpolithus as used by ,linnaeus1 for seeds that cannot be assigned to a systematic position or which do not exhibit any distinctive characters worthy of emphasis by the institution of a special name4 ,the generic term ,holcospermum1 recently proposed by ,nathorst#ajef1 is a suitable name for this type of seed2 as defined by the author1 it includes seeds that may be radiospermic or platyspermic4 ,specimens of the type-species1 ,h4 dubium#ajeg1;from the ,lower ,carboniferous beds of ,spitzbergen1 agree closely in size and shape with some examples of ,rhynchogonium and ,boroviczia1 but they are distinguished by prominent ribs extending the whole length of the cast4 ,in some seeds similar to ,h4 sulcatum the ribs form sharp ridges1 but the difference between rounded and sharp ridges is often determined by the method of preservation3 a specimen deprived of its outer flesh would form a cast more sharply ribbed than a seed in which the sarcotesta had been moulded on to the ribbed sclerotesta4 ,on the other hand some ribs are formed by blunt sclerotestal folds as in ,colpospermum3 both types of ribbing are included in the genus ,holcospermum4 ii4 ,other ,genera4 ,malacotesta4 ,williamson4 ,this generic name was instituted by ,williamson#ajeh for a petrified seed from the ,coal ,measures of ,lancashire which he named ,malacotesta oblonga3 the type-specimen is a small seed #f-g mm4 long characterised by a thick fleshy integument4 ,the structure is however insufficiently known to admit of a satisfactory comparison of the imperfectly preserved specimen figured by ,williamson with other types4 ,thysanotesta4 ,nathorst4 ,nathorst#ajei founded this genus on a single seed from the ,lower ,carboniferous plant-beds of ,spitzbergen which exhibits features sufficiently distinctive to justify its recognition as the type of a separate genus4 ,thysanotesta sagittula ,nathorst4 ,the type-specimen is a long and narrow seed1 #bj mm4 long1 ovate below and prolonged apically into a slender beak1 #h mm4 in length1 which probably represents a micropylar tube2 the beak bears numerous stiff hairs 7fig4 #ejf1 ,f74 ,the seed closely resembles a carpel of ,erodium without the horizontal part of the awn4 ,there is no evidence as to the nature of the parent-plant but the species affords an interesting example of a ,palaeozoic seed apparently adapted for wind-dispersal1 or possibly the bristles may have served the same purpose as in the fruits of ,erodium4 ,attention is called elsewhere#ajfj to the frequent resemblance of ,palaeozoic seeds such as ,thysanotesta to fruits of recent flowering plants4 ,carpolithus4 ,linnaeus4 ,nathorst#ajfa has pointed out that this generic name was employed by ,linnaeus for fossil fruits3 in the form ,carpolites 7,sternberg7 or ,carpolithes#ajfb it has been widely used and differently defined by authors1 usually in a comprehensive sense including fossil seeds from both ,palaeozoic and ,mesozoic strata which cannot be assigned to a definite position in the plant-kingdom4 ,it is desirable to adopt some designation for seeds from strata of different ages which do not exhibit any features sufficiently distinctive to justify the creation of a special genus4 ,by employing such a name as ,carpolithus1 without attempting to define its characters within prescribed limits1 for casts or impressions of seeds which are not distinguished by any striking characters and cannot be allocated to any particular section of seed-bearing plants the unnecessary multiplication of generic titles is avoided3 when any additional data are obtained differentiating particular types from other forms of ,carpolithus the provisional term should be superseded by some distinctive generic name4 ,among seeds from the ,coal ,measures there are several examples of both large and small types without any regular ribs or lacking such features as serve to distinguish the genera already described1 which are appropriately included in ,carpolithus4 ,the two species ,carpolithus ,wildii ,kidst4#ajfc and ,c4 bivalvis ,goepp4#ajfd are two examples of seeds from ,upper ,carboniferous rocks which it is desirable to refer to this comprehensive genus pending further discoveries as to their morphological features4 ,the ,jurassic species ,c4 conicus ,lind4 and ,hutt4#ajfe is another type which it has been customary to include in ,carpolithus4 7,microspermum4 ,arber47 ,the generic name ,microspermum has recently been proposed by ,arber#ajff for some ,westphalian seeds described by ,carpentier#ajfg from the ,north of ,france as ,carpolithes8 samaroides and for similar fossils from the ,middle ,coal ,measures of ,nottingham4 ,the supposed seeds are small1 ovate or pyriform bodies1 #e-ab mm4 long and #be-f mm4 broad1 with one extremity broadly rounded and the other acute3 one side is keeled1 the other grooved1 and a large foramen occurs near the broader end and on the grooved surface4 ,arber emphasises the fact that the specimens are symmetrical in one plane only4 ,as the author of the genus points out the morphological nature of the fossils is not thoroughly established1 nor is the parent-plant known4 ,in view of the ill-defined characters of the specimens so far discovered it is hardly desirable to institute a new generic name implying their seed-nature2 moreover ,microspermum has previously been employed for a genus of ,compositae4 ,an examination of specimens leads me to doubt their seed-nature and it would seem more likely that they are foliar organs1 possibly bracts which originally bore seeds or sporangia4 99 99 99 99 99 ,an examination of some of the specimens of supposed ,permian seeds for which ,geinitz#ajfh proposed the generic name ,guilelmites convinced me that they are inorganic structures1 probably nodules in shale smoothed and rounded by slickensiding4 ,,chapter ,,xxxvi4 ,,cycadophyta4 ,the term ,cycadophyta1 suggested by ,nathorst#ajfi1 is used in a comprehensive sense to include both recent ,cycads and the much larger number of extinct types which it is customary to speak of as ,cycadean plants or fossil ,cycads4 ,the designation #8,cycads' in the case of the majority of the fossil forms is1 however1 open to criticism on the ground that they differ too widely from existing genera to be associated with them in one class4 ,it would be pedantic and inconvenient to give up the almost universal practice of extending the term ,cycad beyond the limits defined by the characters of recent species4 ,the important point is to adopt some classification which gives expression to our views as to the degree of affinity between recent and extinct types4 ,in a considerable number of cases1 especially impressions of presumably ,cycadean fronds and stems that occur without any fertile shoots1 it is impossible to determine the degree of relationship to modern types4 ,it was with a view to a rational group-designation for such fossils that ,nathorst proposed the term ,cycadophyta1 including in it the two classes ,cycadales and ,bennettitales4 ,the ,cycadales comprise the recent genera and such extinct types as may legitimately be included in the same class1 but as we shall see later there are hardly any fossil species that can be assigned to this section on thoroughly satisfactory grounds4 ,the term ,bennettitales is used by ,engler1 ,nathorst1 and several other authors as a class-designation for a large number of ,mesozoic ,cycads agreeing in their more important morphological characters with the ,lower ,cretaceous stems on which ,carruthers#ajgj founded the genus ,bennettites1 placing it in a new tribe1 the ,bennettiteae4 ,some authors have followed ,carruthers in the use of the family-name ,bennettiteae for a subdivision of the ,cycadales equal in rank to the ,cycadaceae1 while others1 wishing to give greater emphasis to the difference between the extinct and recent plants1 prefer to adopt the class-name ,bennettitales4 ,carruthers regarded ,bennettites as occupying the same position in relation to other ,cycads as ,taxus holds with regard to the cone-bearing members of the ,coniferae4 ,the adoption of ,bennettitales is intended to convey the impression that the class is more distantly related to the recent ,cycads than is implied by the analogy of ,taxus4 ,nathorst#ajga1 as the result of his discovery of certain reproductive organs associated with some ,rhaetic fronds described as ,dioonites spectabilis1 proposed a third subdivision1 the ,dioonitales1 but he subsequently#ajgb restored the fronds to their original designation ,nilssonia pterophylloides1 and on further examination found that the supposed microspore-bearing organs were seeds4 ,nilssonia pterophylloides would therefore find a more natural place in the class ,nilssoniales instituted by ,thomas#ajgc4 ,,bennettitales4 ,cycadeoidea4 ,buckland4 ,in #ahbg ,buckland#ajgd proposed the generic name ,cycadeoidea for some petrified stems from the ,purbeck beds in the ,isle of ,portland and published a description of two species1 ,cycadeoidea megalophylla and ,c4 microphylla4 ,brongniart#ajge considered ,buckland's term ,cycadeoidea inappropriate and proposed in its place ,mantellia1 the type-species being ,mantellia nidiformis ,brongn41 the ,portland stem which ,buckland a month or two later called independently ,cycadeoidea megalophylla4 ,subsequently ,brongniart#ajgf withdrew ,mantellia as it had been previously used by ,parkinson for a sponge and substituted ,cycadites4 ,some years later ,carruthers#ajgg revived ,mantellia for a type of ,cycadean stem from ,portland though one species1 apparently indistinguishable from those referred to ,mantellia1 he named ,bennettites portlandicus4 ,there is no adequate reason for the retention of the generic name ,mantellia4 ,the close resemblance of the short and thick stems 7#ab-cj cm4 in height7 described by ,buckland to those of some recent ,cycads was recognised by ,robert ,brown and ,loddiges and the former suggested to ,buckland the inclusion of the fossils in a new family ,cycadeoideae4 ,it was this suggestion that led ,buckland to adopt ,cycadeoidea as a generic name4 ,in a later account of the ,portland stems ,buckland#ajgh1 in deference to ,brongniart's opinion1 substituted ,brongniart's name ,cycadites for ,cycadeoidea4 ,it is noteworthy that no reference is made in the original description to the occurrence of lateral shoots among the persistent petiole-bases that encase the ,portland stems1 but in a later account such shoots are represented in one of the figured stems and are compared with the buds occasionally produced on stems of ,cycas#ajgi4 ,the subsequent researches of ,carruthers#ajhj demonstrated the reproductive nature of precisely similar lateral shoots in the stem on which he founded the genus ,bennettites4 ,the generic name ,echinostipes given by ,pomel#ajha1 who had a passion for instituting new nomenclature1 to ,buckland's ,portland stems has not been adopted3 his genus ,crossozamia proposed for certain stems and fronds was revived by ,carruthers#ajhb but has not been generally used4 ,a further complication in the nomenclature of ,cycadean stems was introduced by ,saporta's institution#ajhc of ,bulbopodium and ,cylindropodium3 in the former genus he included the small ovoid stem figured by ,lindley and ,hutton as ,cycadeoidea pygmaea#ajhd and two ,french ,jurassic species which might reasonably be assigned to ,cycadeoidea4 ,to ,cylindropodium were referred some large ,french stems from ,jurassic strata3 an examination of the type-specimens in ,paris convinced me that they are typical forms of ,cycadeoidea4 ,as ,ward#ajhe has pointed out1 both ,saporta's genera may be merged in ,cycadeoidea4 ,fliche and ,zeiller#ajhf also include the small globular stems named by ,saporta ,bulbopodium in the older genus ,cycadeoidea3 one such type from the ,portlandian of ,boulogne is described by these authors as ,cycadeoidea pumila4 ,saporta also proposed the name ,platylepis#ajhg1 the type-species being ,cycadeoidea micromyela ,mor41 from the ,lias of ,calvados1 which has recently been investigated by ,lignier#ajhh who wisely adopts ,morire's designation4 ,another unnecessary generic name is ,schizopodium given by ,morire to a stem1 ,s4 ,renaulti#ajhi1 regarded by ,lignier as indistinguishable specifically from ,c4 micromyela4 ,the two names ,cycadeoidea and ,bennettites have been used by authors for stems which are unquestionably generically identical and as is often the case much confusion has been caused through the failure of palaeobotanists to arrive at an agreement4 ,lester ,ward1 a staunch advocate of the rule of priority1 repeatedly pointed out that ,buckland's name ,cycadeoidea should take precedence of ,bennettites on the ground that stems for which these genera were instituted are clearly of the same type1 and he added that the older genus1 though abandoned by its author1 cannot be given up without violating the inexorable rules of priority4 ,on the other hand it has been urged that the genus ,bennettites as defined by ,carruthers is characterised by the possession of 7i7 fertile shoots bearing strobili and 7ii7 vegetative organs exhibiting certain anatomical characters4 ,buckland's species of ,cycadeoidea1 though bearing lateral shoots1 are not well enough preserved to afford definite information as to the morphological features of the strobili1 nor have we satisfactory data with regard to the degree of resemblance between the vegetative features of ,bennettites and the ,portland stems4 ,carruthers laid stress on the elliptical section of the stele in ,bennettites in contrast to the cylindrical cylinder of ,buckland's ,cycadeoidea trunks4 ,subsequent research has shown that this difference is not in itself a valid criterion either of generic or specific rank but1 as ,wieland says1 it is an open question to what extent the stem structure of ,cycadeoidea and ,bennettites agrees4 ,the probability is that were our knowledge of the ,portland stems less incomplete1 they would be found to possess no anatomical features inconsistent with this generic union4 ,granting the correctness of this view1 the adoption of the later generic term would be a reasonable course to follow on the ground that it stands for stems showing well preserved structure1 while ,cycadeoidea was in the first instance applied to stems showing only partially preserved stumps of strobili1 and the name was not retained by its author4 ,graf ,solms-,laubach#ajij and some other authors have used ,bennettites for ,cycadean stems possessing strobili of known structure such as those of ,bennettites ,gibsonianus1 reserving ,cycadeoidea for similar stems but without strobili sufficiently well preserved to afford evidence of morphological characters4 ,this practice ,i followed in #ahieajia1 but my usage of the two generic names has not been consistent1 the name ,cycadeoidea being afterwards employed#ajib in a more comprehensive sense4 ,the investigation of the reproductive shoots of ,american ,lower ,cretaceous and ,upper ,jurassic ,cycadean stems#ajic has demonstrated the practical identity of their ovulate strobili with those of the ,english ,bennettites4 ,it is clear that the ,american stems as well as numerous specimens from ,italy and other ,european localities are generically inseparable from ,bennettites4 ,the adoption of ,cycadeoidea by ,wieland1 following ,ward1 has naturally strengthened the claim of ,buckland's genus at least so far as wide usage is concerned1 and with some reluctance ,i propose to fall in with this terminology and for the sake of convenience to give up the use of ,bennettites4 ,among ,mesozoic ,cycadean stems agreeing with those of recent genera in habit and in the presence of an armour of persistent leaf-bases are several which afford no evidence either of the occurrence of fertile shoots or of lateral shoots with terminal flowers4 ,to such stems the name ,cycadeoidea has been applied1 the designation ,bennettites being restricted to stems with lateral fertile shoots3 this practice of treating the absence of reproductive shoots as a characteristic feature of ,cycadeoidea is regarded by ,wieland as illogical and artificial2 and if1 as seems probable1 he is correct in believing that the majority of the ,mesozoic ,cycadean plants culminated their vegetative period by prolific development of flowers1 the absence of flowering branches would be contingent on a certain stage of development and not a generic character4 ,dr ,stopes#ajid has recently published facts with regard to the anatomical features of ,cycadean stems which have a bearing on the vexed question of nomenclature1 but are more important from a morphological point of view as they indicate a closer agreement between certain types of ,lower ,cretaceous stems and those of ,cycas and other recent genera1 in which successive rings of vascular tissue are developed1 than has previously been recognised4 ,in her diagnosis of ,cycadeoidea she includes the following statement3 #8,in its internal anatomy the trunk shows two or more 7up to eight are recorded7 zones of secondary wood1 the zones composed of distinct series of tracheids each more or less regularly arranged in radial sequence4' ,it is claimed that the addition of this character constitutes for the first time a clear distinction between ,cycadeoidea and ,bennettites4 ,dr ,stopes states that the two stems on which ,buckland founded the genus ,cycadeoidea are lost and adds that ,buckland's type has certain anatomical features which are not found in ,bennettites4 ,buckland in his description of ,c4 microphylla states that there are #8two laminated circles' in the stem instead of the usual single cylinder1 a character suggestive of ,cycas4 ,in the original figure of this species there are no indications of any lateral fertile shoots though1 as ,dr ,stopes says1 many of the ,portland stems undoubtedly possessed such flowers4 ,this author makes no reference to ,buckland's later description of ,c4 microphylla3 in this it is stated that the stem bears numerous buds rising from the axillae of petioles1 and these are shown in the illustration#ajie4 ,without access to the actual specimen it is impossible to say whether or not the two #8laminated circles' described and figured by ,buckland#ajif are two distinct cylinders or parts of one cylinder separated by the infiltration of some inorganic substance4 ,in his description of ,cycadeoidea ,yatesii ,carruthers spoke of the occurrence of two cylinders of wood1 and this was confirmed in a subsequent account of the type-specimen#ajig4 ,dr ,stopes gives a fuller account of ,carruthers' type and re-confirm a the existence of two vascular cylinders2 she also describes a new species1 ,c4 buzzardensis#ajih 7fig4 #egh71 in which there are #c-h or more cylinders4 ,neither of these stems affords any evidence of the possession of fertile shoots2 they agree closely with stems of the ,bucklandia type in their comparatively slender habit and differ in this respect from ,buckland's ,portland species4 ,the occurrence of more than one vascular cylinder in the stems ,cycadeoidea 7 ,bucklandia7 ,yatesii and ,c4 7 ,bucklandia7 buzzardensis suggests the possibility that this feature was characteristic of other species included in ,bucklandia4 ,it is clear that some at least of the stems referred to the genus ,bucklandia bore flowers of the ,williamsonia type#ajii1 and it is not improbable that the stems described by ,dr ,stopes as ,cycadeoidea ,yatesii and ,c4 buzzardensis 7fig4 #egh7 possessed fertile shoots comparable with those of the ,middle ,jurassic species ,w4 gigas4 ,dr ,stopes's contribution1 while establishing a close agreement in anatomical features between some ,lower ,cretaceous stems and those of ,cycas1 does not warrant the further conclusion that these stems were in other morphological characters closely allied to modern ,cycads4 ,the main features of ,cycadeoidea may be summarised as follows3 ,the principal trunk is generally unbranched 7fig4 #ejg7 and identical in habit with some species of ,macrozamia1 ,dioon1 and ,encephalartos 7cf4 figs4 #cgi1 #chb72 in some species1 e4g4 ,cycadeoidea ,marshiana1 ,c4 superba#aajj1 ,c4 nana#aaja1 the plant is represented by several approximately equal1 thick1 tuberous stems1 in some cases easily separated from one another3 a similar clustered habit is exhibited by certain forms of ,encephalartos4 ,the size of a ,cycadeoidea trunk varies from a few centimetres in length with a diameter of similar dimensions1 as in ,c4 pumila1 to over a metre long as in ,c4 gigantea 7fig4 #ece71 or as much as #c-d metres in ,c4 ,jenneyana with a diameter of about half a metre4 ,the surface is covered with persistent leaf-bases1 exactly as in many recent ,cycads1 embedded in a thick mass of ramental scales which often stand out as a prominent reticulum1 the petioles having partially decayed before the penetration of the mineralising solution through their harder tissues 7fig4 #ejg74 ,on the conical terminal bud preserved in some stems 7fig4 #ecf7 the foliage-leaves are replaced by linear scales4 ,the leaf-bases often show the vascular bundles which form a simpler system than in the majority of recent species1 their arrangement being1 as ,wieland says1 more ,fern-like2 they form a series of collateral strands following the outline of the petiole-base#aajb with a ,u-shaped invagination in the middle of the upper face 7fig4 #eag1 ,a74 ,beyond the structure of the bundles at the base of the fronds and in the cortex of the stem our knowledge of the anatomy of the vascular supply of the rachises is very meagre4 ,at the petiole-base each bundle consists either entirely of radial rows of centrifugal scalariform tracheids and medullary rays usually one-cell broad 7fig4 #eai1 ,b7 or of centrifugal and centripetal xylem in varying proportions4 ,the ground-tissue is well supplied with large secretory canals and in the larger leaf-bases there is a considerable development of periderm at the surface 7fig4 #eag1 ,b7 as in recent ,cycads4 ,the ramenta formed from the epidermal cells consist in most species of fairly broad scales one-cell thick at the edges and broader in the middle2 in ,cycadeoidea nigra#aajc they are generally one-cell thick throughout and similar ramenta are common in ,c4 ,gibsoniana 7fig4 #eag1 ,b74 ,in ,c4 micromyela unicellular hairs replace the scaly ramenta1 but transitional forms occur between hairs and scales4 ,in ,williamsonia scotica 7fig4 #efb7 and in an ,indian species of that genus the ramenta are exclusively long hairs as in recent ,cycads1 the scale-form of the ramenta in ,cycadeoidea being a ,fern-character4 ,the degree of development of the ramental tissue varies in different species2 in ,c4 ,stilwelli and ,c4 excelsa it is feebly developed while in ,cycadeoidea micromyela the ramenta almost cover the exposed leaf-base armour4 ,the exceptional abundance of the ramental scales is a striking characteristic of some ,american stems referred to a separate genus1 ,cycadella#aajd4 ,in the abundance of the ramental tissue1 in the compact structure of the well protected cones1 and in the thickly cuticularised epidermis of the bracts and leaves ,cycadeoidea exhibits xerophilous characters in a very high degree4 ,illustration3 ,fig4 #ejg4 ,cycadeoidea marylandica4 ,the first ,american stem to be described4 ,on the side of the stem shown in the photograph there are about #cj young strobili scattered among the leaf-bases4 7,after ,wieland2 nat4 size47 ,illustration3 ,fig4 #ejh4 ,cycadeoidea ,wielandi4 ,transverse sections of the secondary xylem of the stem4 ,a1 the middle region2 ,b1 the inner edge of the xylem4 7,after ,wieland2 #ajj47 ,with very few exceptions the stems of ,cycadeoidea so far described afford no satisfactory evidence of the presence of more than one vascular cylinder in the main stem3 in this respect ,cycadeoidea agrees with such recent ,cycads as ,dioon1 ,ceratozamia1 and ,stangeria4 ,in the stem of ,c4 ,jenneyana the secondary vascular tissue reaches a considerable thickness and shows signs of #8rings' in the xylem1 but these are probably the result of some periodic interference with the uniform growth and not an indication of more than one xylem-cylinder4 ,the secondary xylem 7figs4 #ejh1 #eji7 consists only of centrifugal tracheids with some spiral elements on the inner edge2 though manoxylic1 ,cycadeoidea has more compact wood than that of recent ,cycads2 the medullary rays are #a-b cells broad except near the perimedullary region where they are broader and the individual cells are tangentially stretched 7fig4 #ejh1 ,b74 ,the tracheids are scalariform1 but in ,c4 micromyela1 an exceptional type1 some of the xylem-elements have #a-b rows of separate bordered pits 7fig4 #ech74 ,the phloem 7fig4 #eah1 ,b7 is characterised by an alternation of thick-walled elements and thinner cells#aaje4 ,from the main stele branches are given off to supply the flowering shoots in the form of a cylindrical stele like that of the primary axis1 and each leaf-trace arises as a single bundle which1 in the form of a ,u-shaped strand 7fig4 #eai1 ,a71 pursues a straight course to the leaf-base 7fig4 #eaj7 where it breaks up into several branches 7fig4 #ech1 ,b74 ,both leaf-trace and peduncle stele are given off from the lower edge of a medullary ray4 ,in the parenchymatous cortex large secretory canals 7fig4 #eah1 ,b7 are a conspicuous feature1 and accessory cortical steles similar to those in ,cycas occasionally occur 7fig4 #eaa74 ,the large pith consists of parenchyma and secretory canals1 and internal periderm#aajf may be present2 no medullary bundles have been discovered4 ,illustration3 ,fig4 #eji4 ,cycadeoidea ,wielandi4 ,tangential section of secondary xylem of the stem4 7,after ,wieland2 #ajj47 ,illustration3 ,fig4 #eaj4 ,cycadeoidea sp4 ,a piece of stem showing 7,a7 the persistent leaf-bases in side-view and at b the scars where the bases have broken off1 and 7,b7 the inner face of the same piece with the exposed leaf-traces passing into the leaves2 one of the traces is seen at t in fig4 ,a4 7,from a specimen in the ,british ,museum2 nat4 size47 ,illustration3 ,fig4 #eaa4 ,cycadeoidea ,gibsoniana4 ,stele in the cortex4 7,british ,museum1 #hdjf47 ,illustration3 ,fig4 #eab4 ,cycadeoidea ingens4 ,transverse section of a young frond1 above the tip of the rachis1 embedded in ramenta4 ,the rachis is situated on the upper side of the two ranks of pinnae4 ,the arrow points towards the axis of the stem4 7,after ,wieland2 #d47 ,the correlation of the numerous fronds#aajg preserved in ,mesozoic strata with their parent-stems is seldom possible4 ,it is known that leaves of the ,zamites type were borne on stems 7,bucklandia7 agreeing with ,cycadeoidea in certain features but differing in the habit of the fertile shoots 7fig4 #edb71 and there is evidence that similar stems bore ,ptilophyllum and ,dictyozamites fronds#aajh2 but only unexpanded leaves have been found in actual connexion with ,cycadeoidea stems4 ,wieland#aaji discovered young pinnate fronds1 agreeing in the form of the pinnae with ,zamites and with some forms of ,encephalartos1 embedded in a thick mass of ramental scales in the terminal bud of a stem3 the rachises were erect and the two-ranked pinnae imbricate and folded inwards 7fig4 #eab71 the vernation being like that of ,dioon and not circinate as in ,cycas and ,ferns4 ,the mesophyll of the leathery pinnae is differentiated into palisade and lacunar parenchyma1 and the bundles are said to be #8mesarch' though on this point more information is desirable4 ,each bundle is surrounded by a sheath of thick-walled cells and the same tissue forms ,i-shaped girders as in similar recent leaves4 ,in one species1 ,cycadella ramentosa#aaaj1 the rachis of a young frond found among the leaf-bases had a broad ,u-shaped vascular strand4 ,in most ,cycadeoidea stems a characteristic feature is the occurrence of reduced leaves1 or bracts1 arranged spirally about a cone which sometimes projects slightly beyond the general level of the persistent leaf-bases1 or the cones may be fully developed yet still more or less hidden within the armour of petiole-bases 7fig4 #eag1 ,c74 ,these cones1 or flowers1 are borne at the apex of lateral axillary shoots1 and it is characteristic of the genus that they never project more than a very short distance beyond the truncate stumps of the old leaf-bases4 ,the axis of a flowering branch bears numerous linear1 hairy1 bracts 7figs4 #eac2 #ead1 b7 which with their thick felt of ramenta constitute an efficient protective investment4 ,the summit of a fertile shoot forms a rounded hemispherical cushion 7fig4 #ead71 or the receptacle may be more elongate and conical 7fig4 #eac7 and in some species pyriform#aaaa4 ,the flowers are generally bisporangiate1 but the fact that in flowers with mature microsporophylls the ovules are small and apparently immature 7fig4 #eac7 makes it difficult to determine whether the megasporophylls are merely immature or functionless as in the male flower of ,welwitschia 7cf4 fig4 #hah74 ,it would seem1 however1 that in most cases the flowers were bisexual#aaab 7fig4 #eac74 ,a remarkable feature is the enormous number of flowers on a single stem2 in ,cycadeoidea ,dartoni#aaac1 #ed cm4 long and #ce cm4 broad1 #ejj-fjj flowers were counted on one side4 ,on the other hand the large stem of ,c4 gigantea 7fig4 #ecf7 shows no flowers4 ,all the flowers on a single trunk are approximately in the same stage of development3 it would seem1 as ,wieland points out1 that after a vegetative period of some considerable duration the plant produced a large crop of flowers1 and it is conceivable that as in ,corypha and some other recent ,flowering plants this supreme effort set a limit to the plant's existence4 ,in the development of flowers from the old stem ,cycadeoidea affords a striking example of cauliflory4 ,illustration3 ,fig4 #eac4 ,cycadeoidea4 ,restoration of an unexpanded bisporangiate strobilus with some of the hairy bracts removed4 ,compare ,cycadeoidea dacotensis1 figs4 #ebi1 #ecj4 7,after ,wieland2 ca nat4 size47 ,illustration3 ,fig4 #ead4 ,ovulate strobilus of ,cycadeoidea4 ,longitudinal section showing the pith1 m1 stele1 x1 p1 and cortex1 c1 of the stem1 the ovulate strobilus with bracts1 b1 seeds1 s1 etc41 enclosed by foliage-leaves1 l2 a1 insertion of leaves on the stem2 d1 insertion of disc of microsporophylls4 7,after ,wieland47 ,the structure of the flowers is one of the most obvious differences between ,cycadeoidea and recent ,cycads 7cf4 figs4 #cic1 #cid74 ,the bisexual flowers of the fossil stems are comparatively small1 not exceeding a few centimetres in length1 like a hen's egg or a medium-sized pear and in marked contrast to the male and female cones of modern ,cycads 7cf4 figs4 #cic1 #cid74 ,a verticil of pinnate microsporophylls is attached by a circular collar formed of the concrescent bases of the sporophylls to the lower portion of the receptacle2 each pinnule bears several shortly-stalked synangia divided into loculi containing microspores usually with smooth walls and similar1 except in their larger size1 to those of modern ,cycads 7fig4 #ecb74 ,sections of some microspores figured by ,wieland#aaad show what appear to be cells in the spore-cavity1 but they are larger than ordinary prothallial cells and their true nature is doubtful4 ,we lack information both as regards the nature of the male gametes and the tissue formed on the germination of the spores4 ,the free portions of the microsporophyll-whorl may consist of as many as #bj pinnate sporophylls1 but the number is generally smaller2 these are much longer than the ovulate part of the flower and in an immature state the ends of the sporophylls are bent inwards and downwards 7fig4 #eac7 between the bracts and the receptacle4 ,after expanding and shedding the spores the whole male disc is thrown off leaving a narrow rim below the hemispherical or conical receptacle 7fig4 #ead1 d74 ,the sterile distal end of a microsporophyll is generally slightly expanded and spathulate2 in ,c4 colossalis#aaae it bears a pair of wing-like appendages 7fig4 #ecc74 ,the upper part of the receptacle is covered with two kinds of organs which together form a layer of uniform depth2 these are believed to be homologous1 foliar structures2 the majority are sterile and have the form of slender long and narrow appendages 7fig4 #ead7 each normally with a single axial vascular strand4 ,these so-called interseminal scales increase in breadth in the apical region and form polygonal summits less than a millimetre in breadth or exceeding #b mm4 ,the low pyramidal apices of the interseminal scales give a mosaic-like appearance to the surface of the ovulate receptacle 7fig4 #eae74 ,in the lower part of the receptacle these sterile sporophylls are the only appendages1 but over the greater part of the receptacle they are intermixed with a smaller number of similar appendages which bear a single terminal orthotropous ovule 7fig4 #ead1 s74 ,each ovule-bearing organ or megasporophyll 7seed-stalk7 is surrounded by #e--f interseminal scales1 and the narrow cylindrical micropylar tubes are readily distinguished from the sterile sporophylls in surface-view 7figs4 #eaf1 #efd74 ,the seeds appear to be exalbuminous and the embryo is dicotyledonous 7figs4 #eaf1 #eba1 #ebc7aaaf4 ,the seeds are very small in comparison with those of living ,cycads4 ,the structure of the megasporophylls1 both sterile and fertile1 is described in more detail in the account of ,cycadeoidea ,morierei and other forms4 ,fig4 #eaf represents a longitudinal section of one of the smallest seeds of ,cycadeoidea1 between #c and #d mm4 long2 an embryo occupies the greater part of the seed-cavity3 the micropylar tube is formed of three layers1 a strong inner palisade-layer1 a thin middle layer1 and an outer palisade-tissue1 the interior of the tube being filled with parenchyma2 at the shoulder of the seed above the root-end of the embryo the surface of the testa is characterised by #e-f wings formed by the radial extension of palisade-cells4 ,after the shedding of the spores and the abscission of the microsporophylls the flowering shoot probably increased slightly in length1 thus pushing the ripening seeds beyond the ends of the surrounding leaf-bases4 ,the ripe flowers were eventually cut off by an absciss-layer immediately below the receptacle 7figs4 #eba1 ,c1 a2 #ebb1 a71 large cup-like depressions being left on the surface of the stem 7fig4 #ecd74 ,the ovulate cone on which the species ,cycadeoidea ,morierei is founded probably represents the condition of a naturally detached flower of a ,cycadeoidea4 ,it is possible that the detached flowers freed from their encircling bracts may have been edible1 the small seeds being dispersed by animal agency4 ,illustration3 ,fig4 #eae4 ,cycadeoidea sp4 ,surface-view of a young ovulate strobilus showing the swollen ends of interseminal scales grouped about the circular micropyles4 7,after ,wieland2 #aj47 ,illustration3 ,fig4 #eaf4 ,cycadeoidea ,dartoni4 ,longitudinal section of seed with embryo4 7,after ,wieland2 #ai47 99 99 99 99 99 ,the splendid petrified stem1 ,cycadeoidea etrusca ,cap4#aaag1 one of the treasures of the ,bologna ,museum1 was found on a tomb #bj miles west of that city where it was doubtless placed by the ,etruscans who obtained it from the ,upper ,jurassic scaly clays in the ,apennine ,hills4 ,it was in an imperfectly preserved flower of this fossil that ,graf ,solms-,laubach discovered some microspores1 but it was not until ,wieland's examination of the more complete ,american stems that information was obtained as to the spore-bearing organs4 ,another ,italian stem1 ,cycadeoidea montiana ,cap41 was described in #agec as a #8congeries of barnacles#aaah4' ,the specimen named by ,goeppert ,raumeria ,reichenbachiana#aaai was described in the middle of the eighteenth century as a mass of ,hippurites or coral cups3 this was found in a swamp in ,galicia and is now one of the most striking objects in the ,dresden ,museum2 a brief account of it is given on page #dji4 ,in #ahei ,tyson discovered two large trunks in the ,potomac beds of ,maryland for which ,fontaine subsequently proposed the name ,tysonia marylandica#aabj1 but as ,ward pointed out the species is clearly a ,cycadeoidea 7fig4 #ejg74 ,in #ahid ,lester ,ward#aaba recorded several additional stems from ,tyson's locality4 ,it is1 however1 from the ,black ,hills of ,dakota1 an isolated spur of the ,rocky ,mountains1 formed of older rocks encircled by ,lower ,cretaceous strata#aabb1 that the greatest number of ,cycadean trunks have been obtained3 the magnificent collection now in the ,yale ,museum is largely due to the energy and munificence of the late ,prof4 ,marsh4 ,from the ,upper ,jurassic beds in ,carbon ,co41 ,wyoming#aabc1 several stems have been collected1 and a preliminary study of their external features led ,ward to institute #bj species of a new genus ,cycadella4 ,stems have also been discovered in the ,freezout ,hills of ,wyoming and additional specimens have been found in the ,potomac formation of ,maryland4 ,the discovery of over #ajjj specimens of ,cycadean stems in the ,lower ,cretaceous and ,upper ,jurassic beds of a few localities in the ,united ,states bears striking testimony to the abundance of these extinct ,gymnosperms during the latter part of the ,mesozoic era4 ,it is perhaps true that1 as ,lester ,ward wrote1 #8,cycads are to the vegetable kingdom what ,dinosaurs are to the animal1 each representing the culmination in ,mesozoic times of the ruling ,dynasties in the life of their age#aabd4' ,although the number of stems obtained from ,european countries is relatively small1 the abundance of specimens in the ,upper ,jurassic strata of the ,isle of ,portland and ,northern ,italy and their occurrence in ,belgium#aabe1 ,france1 ,germany1 ,austria1 ,poland1 ,india and elsewhere1 together with an abundance of ,cycadean fronds in practically all ,jurassic and ,lower ,cretaceous plant-bearing beds1 demonstrate the dominant position of the ,bennettitales4 ,the occurrence of the genus ,williamsonia in many ,european localities as well as in ,india1 ,afghanistan1 and other countries1 and the not infrequent occurrence of stems assigned to ,bucklandia1 ,yatesia1 ,cylindropodium1 and other genera furnish evidence of the rich development of the ,bennettitales in later ,jurassic and ,lower ,cretaceous floras4 ,wieland's recent discovery#aabf of numerous ,cycadean fronds1 ,williamsonia flowers1 and stems in ,liassic rocks in ,mexico shows that the group had already assumed an important position in the early part of the ,jurassic period4 ,the memoir by ,carruthers#aabg on ,british ,cycadean stems contains the first account of the morphological features of ,bennettitalean flowers based on petrified material4 ,in #ahia ,solms-,laubach contributed an important paper on the ,bennettitean flower and several years later ,lignier#aabh contributed additional data derived from a careful study of a well preserved strobilus#aabi from the ,gault of ,normandy4 ,wieland's researches#aacj added very greatly to our knowledge1 particularly with regard to the morphology of the microsporophylls4 ,among the earlier descriptions of the reproductive organs of the ,bennettitales is ,buckland's account#aaca of a specimen from the ,inferior ,oolite of ,charmouth1 ,dorset 7fig4 #efj71 which he referred to the genus ,podocarya 7 ,williamsonia ,bucklandi#aacb73 a thorough examination of the type-specimen1 which unfortunately cannot be found1 would probably furnish many important facts4 ,cycadeoidea 7,bennettites7 ,gibsoniana 7,carruthers74 ,cycadeoidea 7,bennettites7 ,saxbyana 7,brown74 ,these two species serve to illustrate the type of stem for which ,carruthers instituted the tribe ,bennettiteae and the genus ,bennettites4 ,bennettites ,gibsonianus is the most important of the five species described by ,carruthers#aacc1 as it was from its fertile shoots that information was first obtained as to the nature of the ovulate strobili of the ,bennettitales4 ,b4 ,saxbyanus#aacd1 originally described as ,cycadites ,saxbyanus from a specimen found by ,mr ,saxby at ,bonchurch in the ,isle of ,wight and represented by ,wealden examples from ,brook ,point1 is chiefly interesting for the clear preservation of the anatomical features of the stem4 ,three other species were also described by ,carruthers2 they are3 ,bennettites maximus ,carr41 a large stem similar to ,b4 ,saxbyanus1 in the ,museum of the ,geological ,survey2 ,b4 portlandicus from the ,lower ,purbeck of the ,isle of ,portland1 in the collection of the ,geological ,society2 and ,b4 ,peachianus1 a piece of a compressed stem1 in the ,british ,museum1 from the ,upper ,jurassic of ,helmsdale in ,n4,e4 ,scotland4 ,illustration3 ,fig4 #eag4 ,cycadeoidea ,gibsoniana4 ,a1 transverse section of petiole showing vascular bundles and ramenta2 ,b1 portion of ,a enlarged showing periderm and ramenta4 ,c1 tangential section of stem with leaf-bases1 ramenta 7black7 and two flowers1 #a1 #b4 7,a1 slightly enlarged1 ,manchester ,collection1 ,r1 #ajfi2 ,c1 after ,carruthers47 ,cycadeoidea 7,bennettites7 ,gibsoniana4 ,this species was founded on a petrified portion of a large stem of ,lower ,greensand age discovered by ,mr ,gibson in ,luccomb ,chine in the ,isle of ,wight3 the type-specimen is represented by pieces of the original block in the ,british ,museum and in one of the ,museums at the ,royal ,gardens1 ,kew4 ,the following description is based partly on the published accounts and in part on an examination of sections in the ,british ,museum1 the ,manchester ,university ,museum1 and in ,dr ,scott's collection4 ,the elliptical form of the stem and vascular cylinder as seen in transverse section1 regarded by ,carruthers#aace as a feature characteristic of the genus1 has no morphological significance and is in part at least due to compression4 ,in the large pith1 the armour of persistent petiole-bases separated by dense ramental scales 7fig4 #eag1 ,a1 ,b71 and in habit1 ,cycadeoidea ,gibsoniana agrees generally with the stems of many recent ,cycads1 but the resemblance of the vegetative organs is in marked contrast to the differences exhibited by the reproductive shoots4 ,the pith consists of parenchyma with scattered secretory ducts but no medullary vascular bundles4 ,in the pith of ,cycadeoidea ,peachiana there are patches of tissue superficially resembling vascular strands1 but these are probably bands of internal phloem like those described by ,solms-,laubach#aacf in some ,italian stems4 ,in none of the ,english stems are there any clear indications of the occurrence of more than one cambium in the stele4 ,the secondary xylem is entirely centrifugal with some smaller crushed elements1 presumably protoxylem1 at the inner edge where the medullary rays are especially broad4 ,the xylem is of the manoxylic type 7fig4 #eah1 ,a7 as in recent ,cycads2 though the medullary rays1 #a-b cells broad1 are rather smaller than in recent species4 ,the tracheids are scalariform as in ,stangeria 7fig4 #cig74 ,as in recent ,cycads there is a broad cylinder of secondary phloem 7fig4 #eah1 ,b7#aacg composed of alternate layers of thick-walled and thinner elements--sieve-tubes and parenchyma3 traces of lateral sieve-plates occur on some of the elongated elements4 ,each leaf-trace arises as a single strand from the lower edge of a mesh formed by the large inner end of a medullary ray3 on emerging into the inner cortex the trace has the form of a ,u-shaped strand 7fig4 #eai1 ,a1 lt7 which passes direct to the petiole1 following a steeply ascending course in ,cycadeoidea ,saxbyana and almost horizontal in ,c4 ,gibsoniana4 ,before entering the base of a leaf the trace breaks up into several collateral strands and these form a simple pattern as seen in a tangential section of the leaf-bases 7fig4 #eag1 ,a1 ,c71 the central bundles on the upper side forming a ,u-shaped involution4 ,there is no indication of any girdling of the foliar bundles4 ,the arrangement of the petiolar bundles is simpler and more ,fern-like than in the majority of existing ,cycads4 ,each vascular bundle consists in the petiole-base mainly of centrifugal secondary xylem and medullary-ray tissue 7fig4 #eai1 ,b72 a group of centripetal tracheids is usually recognisable internal to the protoxylem3 the structure is of the mesarch type with a variable amount of centripetal xylem1 and agrees generally with that in recent ,cycads4 ,illustration3 ,fig4 #eah4 ,cycadeoidea ,gibsoniana4 ,a1 secondary xylem of stem2 ,b1 secondary phloem and part of the cortex with secretory ducts1 s4 7,a1 ,b1 ,british ,museum1 #acbjf47 ,illustration3 ,fig4 #eai4 ,cycadeoidea ,gibsoniana4 ,a1 transverse section of the vascular cylinder of stem1 with leaf-trace1 lt2 c1 cambium1 px1 protoxylem4 ,b1 vascular bundle of petiole4 7,british ,museum47 ,the comparatively narrow cortex is composed of parenchyma with scattered secretory sacs 7fig4 #eah1 ,b1 s71 and occasionally an elliptical vascular strand 7fig4 #eaa7 is present which is probably cauline as are the similar strands in ,cycas4 ,the persistent petiole-bases are covered with ramental scales which form a dense interfoliar packing3 these frequently consist of a single layer of fairly thick-walled cells or1 as seen in transverse section1 of spindle-like scales one-cell thick at the edges and #b-c cells broad in the middle 7fig4 #eag1 ,b74 ,illustration3 ,fig4 #ebj4 ,cycadeoidea ,gibsoniana4 ,ground-tissue of bract4 7,british ,museum4 #dachh47 ,the presence of fertile shoots1 presumably axillary1 is one of the most striking features of ,bennettitean stems4 ,the branching is monopodial and not sympodial as in most recent ,cycads4 ,the nearest approach to the method of branching in ,cycadeoidea is afforded by some stems of ,macrozamia recently described by ,chamberlain#aach4 ,it is not improbable that some of the flowering branches of ,cycadeoidea were branched4 ,solms-,laubach#aaci states that he observed certain characters in the secondary axes of ,cycadeoidea ,gibsoniana which led him to suspect that there may have been fascicled systems of fertile shoots emerging in a body or in close proximity to one another between the leaf-bases of the stem4 ,an example of a branched flowering shoot is described in ,williamsonia scotica#aadj4 ,a fertile shoot agrees in structure with the main axis and ,scott#aada states that the phloem is particularly well developed1 a feature by no means unusual in fertile branches4 ,these lateral shoots 7fig4 #ead7 bear numerous linear bracts each with three collateral vascular bundles1 and ground-tissue composed of thick-walled cells characterised by scalariform pitting 7fig4 #ebj73 secretory sacs are abundant4 ,the hypodermal stereome is especially developed on the inner face of the bracts4 ,the apex of a lateral shoot has the form of a rounded cushion 7figs4 #ead2 #eba1 ,a1 ,c7 similar to the receptacle of many ,composites1 and on this are borne the sporophylls4 ,it is characteristic of ,cycadeoidea that the flowers project very slightly beyond the surface of the stem and the peduncles are not exposed except in tangential sections through the leaf-base armour 7fig4 #eag1 ,c1 #a1 #b74 ,on the fall of the flower or ripe #8fruit1' which is effected by an absciss-layer 7figs4 #eba1 ,c1 a2 #ebb1 a71 a cup-like scar is left on the stem 7cf4 fig4 #ecd74 ,this method of flower-production suggests comparison1 mutatis mutandis1 with the phenomenon of cauliflory in certain recent ,flowering plants2 it is one of the distinguishing features between ,cycadeoidea and stems bearing longer fertile shoots with flowers of the ,williamsonia type4 ,illustration3 ,fig4 #eba4 ,cycadeoidea 7,bennettites7 ,gibsoniana4 ,a1 ,c1 longitudinal sections2 a1 absciss-layer2 b1 bracts2 pr1 #8pericarp'2 s1 scales1 sterile and fertile4 ,b1 transverse section of female flower2 i1 interseminal scales2 m1 megasporophylls4 ,d1 transverse section of seed showing the testa1 t1 separated by a space1 sp1 from the embryo4 ,e1 embryo2 r1 radicle4 7,a1 ,b1 ,d1 ,e1 after ,solms-,laubach2 ,c1 section in the ,british ,museum47 ,fig4 #eag1 ,c1 shows a tangentially cut surface of a portion of the stem of ,cycadeoidea ,gibsoniana with two axillary fertile shoots2 one1 #a1 is cut across below the receptacle and shows the axis surrounded by bracts while the other1 #b1 is seen at a higher level1 above the receptacle1 where the section has exposed the numerous sporophylls4 ,the rounded surface of the receptacle is covered with a dense cluster of long slender appendages1 seed-stalks and interseminal scales1 the latter being much more numerous than the former 7fig4 #eba1 ,a1 ,b74 ,these organs are believed to be homologous foliar structures1 the seed-stalks being megasporophylls and the interseminal scales abortive or potential sporophylls 7see also figs4 #efb1 #efc74 ,fig4 #ead shows the form of a single flower from an ,american stem closely allied to ,cycadeoidea ,gibsoniana4 ,illustration3 ,fig4 #ebb4 ,cycadeoidea ,gibsoniana4 ,longitudinal section of flower showing half the receptacle with part of the absciss-layer1 a4 7,british ,museum47 ,illustration3 ,fig4 #ebc4 ,cycadeoidea ,gibsoniana4 ,seed with embryo4 7,british ,museum1 #dachh47 ,the megasporophylls are more or less polygonal in transverse section3 there is a central concentric vascular strand surrounded by a thick cortex 7fig4 #ebg73 at its upper end the sporophyll bears a single orthotropous seed containing a dicotyledonous embryo 7figs4 #eba1 ,d1 ,e2 #ebc74 ,the vascular strand pierces the base of the testa and expands to form a shallow cup of tracheal tissue in the chalaza2 there are no bundles in the single integument4 ,the testa 7fig4 #eba1 ,d1 t7 consists of three regions1 a median layer of rather large rectangular or palisade-cells with an inner and outer tissue composed of much smaller cells4 ,the testa is prolonged distally as a slender cylindrical column or micropylar tube at the base of which it becomes broader owing to the increase in breadth of the middle or palisade layer4 ,a nucellar beak projects as a cone into the base of the micropylar tube4 ,no pollen-chamber has been found4 ,it is noteworthy that the micropyle is closed in the ripe seeds4 ,internal to the testa there is a crushed membrane separated from the embryo by a space 7fig4 #eba1 ,d1 sp73 this is the remains of the nucellus and1 as ,solms-,laubach points out1 there is no proof that any endosperm was present in the ripe seeds#aadb4 ,the embryo consists of a short axis1 the conical radicle and the very short apex of the epicotyl1 also two equal cotyledons each with a few vascular bundles 7fig4 #eba1 ,d74 ,the long interseminal scales1 as seen in transverse section in the lower part of a flower between the sporophylls1 appear as compressed polygonal organs 7fig4 #eba1 ,b1 i7 with an axial vascular strand surrounded by parenchyma and limited by a strong epidermis2 they pass up between the seed-stalks1 m1 and in the distal end become considerably enlarged 7figs4 #ead1 #eae71 gradually expanding to form a truncate or slightly pyramidal apex 7figs4 #eec1 #efc74 ,the swollen peltate apices of adjacent scales form a continuous covering to the flower interrupted1 except in the lower sterile part of the flower1 by symmetrically disposed cylindrical micropylar tubes 7fig4 #eae74 ,the peripheral interseminal scales form a homogeneous parenchymatous tissue which springs from below the edge of the receptacle 7fig4 #eba1 ,a1 ,b1 pr7 and the individuality of the scales composing this #8pericarp' is indicated by occasional invaginations of the epidermal layer which marks the boundary of the polygonal areas4 ,the structure of the megasporophylls and scales is more fully described in the case of ,cycadeoidea 7,bennettites7 ,morierei#aadc4 ,the flowers of ,cycadeoidea ,gibsoniana appear to be unisexual and ovulate3 in view of the discovery by ,wieland of numerous bisexual fertile shoots on ,american species of ,cycadeoidea it would be reasonable to regard the apparently unisexual flowers of the ,english species as originally bisexual but preserved at a stage subsequent to the loss1 by abscission1 of the disc of microsporophylls4 ,fig4 #ead shows a flower of an ,american ,cycadeoidea practically identical with those of ,c4 ,gibsoniana1 but the remains of the staminate disc are clearly seen at d below the swollen apex of the flowering axis4 ,in the photograph of half of the same region in ,c4 ,gibsoniana reproduced in fig4 #ebb there is no indication of any similar trace of a whorl of microsporophylls4 ,admitting the fact that a shrivelled remnant of the persistent base of a whorl of microsporophylls might easily escape observation1 it is difficult to believe that any fertile leaves ever existed in the flower represented in figs4 #eba1 #ebb4 ,it is equally difficult to regard the specimen represented in fig4 #efa as other than a true unisexual 7ovulate7 flower4 ,cycadeoidea 7,bennettites7 ,morierei 7,saporta and ,marion74 ,the name ,bennettites was adopted by ,lignier for this species which was founded on a detached flower from the ,gault#aadd of ,vaches-,noires1 ,normandy4 ,it was first described by ,morire#aade1 then by ,saporta and ,marion#aadf1 who named it ,williamsonia ,morierei1 and it has since been thoroughly investigated by ,lignier#aadg4 ,there is no evidence as to the nature of the parent-stem though ,morire suggested a possible connexion with ,zamia ,brongniarti ,mor4 7figured by ,saporta#aadh as ,fittonia ,brongniarti7 from the same locality4 ,there can be no reasonable doubt that ,bennettites ,morierei was borne on a lateral branch of a stem of the ,cycadeoidea type3 it is constructed on essentially the same plan as the flowers of ,cycadeoidea 7,bennettites7 ,gibsoniana1 and in both cases there is no indication of the presence of microsporophylls4 ,the type-specimen is #ee cm4 long and #ce cm4 broad1 ovoid1 and characterised by a depressed cushion-like receptacle as in ,cycadeoidea ,gibsoniana4 ,the enveloping bracts with their ramental scales agree generally in structure with those of the ,english species and1 except as regards the ramenta1 with ,williamsonia scotica3 numerous stomata occur on the lower surface2 the ground-tissue consists of thick-walled parenchyma and the narrow pit-canals simulate the scalariform bands in ,cycadeoidea ,gibsoniana 7cf4 fig4 #ebj74 ,the pitted sclerous cells in the bracts of ,w4 scotica are of the same type4 ,there is an anastomosing system of secretory canals1 also several vascular bundles like those in ,c4 ,gibsoniana but more numerous2 the latter are composed of a group of phloem-elements abutting externally on fibres1 a well-defined cambium1 and radially disposed scalariform tracheids3 internal to the protoxylem is a group of elements considered by ,lignier to be centripetal xylem4 ,from the branching and slightly divergent course of the bundles in the upper part of the bracts ,lignier concluded that these organs represent the basal portions of leaves originally provided with a terminal limb4 ,it may be that the small lateral appendages to some of the bracts of ,williamsonia scotica 7fig4 #efa1 l7 afford support to this view4 ,megasporophylls 7seed-stalks and seeds74 ,these organs1 #c-de cm4 long and approximately #ae mm4 in diameter1 are in most cases imperfectly preserved4 ,in transverse section and at a level of #a cm4 above the receptacle a stalk bearing an atrophied seed shows the following features3 an epidermis with very thick internal walls encloses a parenchymatous ground-tissue with an axial conducting strand4 ,at a higher level the epidermal cells have walls of uniform thickness1 and a hypodermal layer of cells with coloured contents is differentiated from the ground-tissue 7fig4 #ebd1 ,d1 ac74 ,as the seed-base is approached the epidermal cells tend to separate from one another and divide longitudinally1 the compact epidermal layer being replaced by an envelope of tubular1 dissociated1 cells 7fig4 #ebd1 ,d1 ,et74 ,similar tubular elements occur in the seed-stalks of ,cycadeoidea ,gibsoniana4 ,a fully developed seed-stalk bearing a complete seed cut across in the middle region shows the following features3 a concentric vascular strand surrounded by thin-walled parenchyma and the coloured hypodermal layer 7fig4 #ebd1 ,d1 ac71 the whole being enclosed in the tubular envelope of epidermal origin 7,et7 which is more strongly developed than in the stalks of imperfect seeds3 there may be as many as #aj-ab tubular cells on one radius4 ,when traced downwards towards the receptacle the tubular envelope decreases in breadth1 though the cells become more numerous and smaller1 until in the immediate neighbourhood of the receptacle the tubular tissue is transformed into a compact parenchyma of large cells each of which corresponds to a group of tubes formed by the septation of the cells4 ,traced upwards this thin-walled parenchyma gradually passes into thick-walled tubes1 and near the seed-base the tubular envelope is reduced to two layers1 an inner consisting of relatively small cells with sinuous radial walls 7the folded layer of ,lignier7 and an outer tubular layer4 ,lignier describes an interesting abnormality1 a bifid seed-stalk enclosed in a common epidermis which he compares with the occasional branching of the seed-stalks of ,ginkgo biloba4 ,illustration3 ,fig4 #ebd4 ,cycadeoidea 7,bennettites7 ,morierei4 ,a4 ,transverse section of the micropylar tube containing the apex of the nucellus2 ,ei1 inner epidermis2 ,tf1 ground-tissue2 e1 outer epidermis with the thickening of the walls shown in a few of the cells4 ,b4 ,transverse section of the upper part of the micropylar tube2 lettering as in fig4 ,a4 ,c4 ,transverse section at the level of the wings formed by the fibrous layer and corresponding to the angles of the seed1 approximately at the level cp in fig4 #ebe2 cn1 nucellar cavity2 ,ei1 inner epidermis of seed-coat2 cf1 fibrous layer of wings1 f1 which extend across the fleshy layer1 tch1 to the radial layer ar 7cf4 fig4 #ebe72 at1 tubular layer2 ,ee1 epidermis of adjacent scale detached from the other tissues1 ase1 along the line of fracture d2 ,,ee1 epidermis of two adjacent scales4 ,d4 ,transverse section of peduncle2 tr1 tracheids2 ac1 coloured subepidermal layer2 ,et1 tubular epidermis1 double in places2 ,,ee1 epidermis formed from neighbouring scales4 7,from ,prof4 ,lignier's drawings2 ,a1 ,b1 ,d1 #aah2 ,c1 #ij47 ,seeds4 ,the seeds 7figs4 #ebe1 #ebf71 #f-g #be-c mm41 are tetragonal or pentagonal in the upper half 7fig4 #ebg1 #a1 #b71 the angles being formed by thick but not very prominent wings of tissue 7fig4 #ebd1 ,c1 cf72 they are orthotropous and have a single integument 7figs4 #ebe1 #ebf74 ,the tubular layer forming the outer portion of a seed-stalk near the seed-base is prolonged over the surface of the testa as a discontinuous covering in the form of isolated or small groups of tubes1 giving a striated appearance to the seeds4 ,this layer though apparently a part of the seed is derived from the neighbouring interseminal scales of which it is the epidermal layer2 it consists of elongated cells and scattered stomata#aadi4 ,the folded layer persists only in the lower part of the seed1 being replaced by a layer of radially extended cells 7radial layer2 ar1 figs4 #ebd1 ,c2 #ebe1 ar2 #ebg1 c7 in the upper region of the seed4 ,in the micropylar region both the tubular and folded layers undergo further change2 the external1 tubular1 layer forms a kind of epidermis 7at1 figs4 #ebd1 #ebe71 the subepidermal layer1 consisting of the radially elongated cells 7figs4 #ebd1 #ebe1 ar2 #ebg1 c74 ,the superficial layer assumes a different aspect in the micropylar region1 its cells being thicker walled1 as are also those of the subepidermal layer 7fig4 #ebd1 ,a and ,b74 ,the micropylar canal 7figs4 #ebd1 #ebe1 cm7 is cylindrical in the lower part but at the apex is reduced to a long and narrow slit bounded by an internal epidermis of radially stretched cells which in the lower portion of the tube are thinner walled and isodiametric4 ,the rest of the testa is differentiated into two regions2 an outer fleshy region immediately internal to the folded 7or radial7 layer and an inner fibrous region next the nucellus1 which is one-layer broad between the wings but opposite the wings it extends radially outwards across the fleshy tissue to the radial layer 7figs4 #ebd1 ,c2 #ebe2 #ebg73 in the winged portion of the seed this tissue forms the inner fibrous portion of the wings but in the lower part of the seed below the wings it forms a single layer of uniform breadth finally spreading out as a basal cup in the chalazal region where it is pierced by the vascular strand4 ,the fleshy portion of the testa forms one layer in the proximal part of the seed and becomes several layers wide between the fibrous wings in the upper part4 ,this fleshy tissue appears to be derived from the coloured1 subepidermal1 layer of the seed-stalk1 while the internal parenchyma is regarded by ,lignier as the equivalent of the fibrous layer of the testa4 ,in the micropylar tube the fibrous layers are replaced by #b-c layers of sclerous cells 7fig4 #ebd1 ,a1 ,b74 ,the testa has no vascular supply3 the concentric strand of the seed-stalk passes through the fibrous tissue at the base of the seed and reaches the base of the nucellus 7fig4 #ebe74 ,the nucellar apex extends into the lower part of the micropyle 7fig4 #ebe1 n71 and in some cases ,lignier noticed an axial canal formed by the breaking-down of the cells which abutted below on a cavity above the embryo1 probably the remains of a pollen-chamber 7figs4 #ebe1 #ebg74 ,no microspores have been found4 ,two dark spots shown at co1 fig4 #ebe1 may represent archegonia but this is doubtful1 especially as the seed contains a well-developed embryo4 ,the nucellus is free from the testa only in the apical region and a dicotyledonous embryo occupies the interior without any trace of endosperm4 ,lignier points out that in some seeds containing embryos the nucellar beak is not completely perforated3 in this fact and in the absence of microspores in the micropylar canals he is inclined to see evidence of parthenogenesis#aaej4 ,illustration3 ,fig4 #ebe4 ,cycadeoidea 7,bennettites7 ,morierei4 ,section of a seed and adjacent interseminal scales4 tm1 micropylar tube2 n1 nucellar beak in the micropylar canal1 cm2 cp1 pollen-chamber2 co1 archegonia 7872 em1 position of the embryo2 ch1 chalaza2 dn1 remains of the nucellus2 af1 fibrous layer passing below into the shell1 cq1 and the peduncle1 ,tf2 tch1 fleshy layer2 ar1 radial and tubular layers represented in the peduncle by the tubular envelope at2 ,ec1 swollen ends of the interseminal scales4 7,from a drawing kindly supplied by ,prof4 ,lignier2 #aj47 ,illustration3 ,fig4 #ebf4 ,cycadeoidea 7,bennettites7 ,morierei4 ,longitudinal section of a seed and interseminal scales4 7,from a photograph supplied by ,prof4 ,lignier47 ,in several respects the seeds of ,cycadeoidea agree with those of ,gnetum3 reference should be made to the account of the seed of ,gnetum africanum in ,chapter lii4 and to the papers referred to in the footnote#aaea4 ,interseminal scales4 ,the young seed-stalks agree very closely with the interseminal scales3 each seed-stalk is surrounded by #e-f scales 7fig4 #ebg7 as in other ,bennettitean flowers 7fig4 #efd74 ,for the greater part of their length the interseminal scales are compressed1 but above the seeds1 where they are free from pressure 7fig4 #ebf71 they become much thicker and form a covering 7#8pericarp'7 as in ,cycadeoidea ,gibsoniana4 ,in its upper region an interseminal scale consists of an epidermis with strongly thickened inner walls1 hypodermal thick-walled cells and parenchymatous ground-tissue with a single axial bundle4 ,in the lower part the scale is more flattened and the thick-walled hypoderm is replaced by thin-walled parenchyma4 ,some of the scales at the periphery of the receptacle where there are no seed-stalks are broader and may have six vascular bundles2 this1 ,lignier suggested1 might be regarded as evidence of the reduction of the interseminal scales from leaves possessing a terminal limb2 but a further examination of scales at the periphery of the flower led him to the conclusion that the distal swelling of the scales is solely due to the hypertrophy of conjunctive tissue and is not the result of the modification of a reduced limb#aaeb4 ,the morphological value of the interseminal scales and seed-stalks has not been definitely settled1 though the probability is that they are homologous organs and foliar4 ,solms-,laubach#aaec suggested that both may be axial1 the seed-stalks representing axes ending in a flower reduced to a single ovule2 or1 he adds1 the seed-stalks may just as well be carpels1 though in that case we should have the unusual phenomenon of terminal seeds4 ,the interseminal scales may be aborted seed-stalks crushed between the latter2 or if the seed-stalks are axes1 the scales may be foliar4 ,he is inclined to see in the scales the bracts and prophylls of seed-stalks to which must be added such bracteoles1 preceding the seed or flower1 as may happen to spring from the seed-stalks4 ,pearson#aaed1 on the assumption that the seed-stalks are axial structures1 institutes a comparison between ,welwitschia and ,bennettites and regards each flower of ,welwitschia as a much reduced ,bennettitean strobilus4 ,lignier believes the interseminal scales to be leaves borne on the swollen apex 7receptacle7 of an axis of the second order1 while the seed-stalks are fertile leaves of a unifoliar bud of the third order possibly axillary though not necessarily so to the interseminal scales4 ,my own view1 influenced by the examination of the immature flower of ,williamsonia scotica1 is that the seed-stalks 7megasporophylls7 and scales are homologous1 the former being sporophylls and the latter sterile foliage leaves1 the whole flower1 as ,wettstein#aaee says1 consisting of a conical axis bearing numerous fertile and sterile carpels enclosed by a perianth of bracts4 ,worsdell#aaef1 who shares elakovsky's opinion that sporophylls were originally radially symmetrical organs bearing a terminal sporangium1 regards the flowers of ,cycadeoidea ,gibsoniana and other species as more primitive than those of recent ,cycads3 he does not see any justification for the view that the ,bennettitalean flowers are in advance of those of existing ,cycadean plants as regards a supposed tendency towards the ,angiospermous type4 ,he maintains that ,bennettites #8shows absolutely no indication of such an advanced structure in its essential organs1 the sporophylls1 which remain primitively radial in structure1 bearing the ovules in a terminal position4' ,illustration3 ,fig4 #ebg4 ,cycadeoidea ,morierei4 ,transverse section of interseminal scales and seeds near the apex of the latter2 seeds #a and #b show the pollen-chamber1 a2 the fibrous layer1 b1 forming wings and extending across the fleshy tissue2 c1 the radial layer2 seeds #c and #d are aborted4 7,after ,lignier47 ,the letters a1 b1 c1 in this figure correspond to cp1 cf1 and ar in figs4 #ebe1 #ebf4 ,cycadeoidea dacotensis 7,mc,bride74 ,mc,bride#aaeg first described this ,lower ,cretaceous species from the ,black ,hills of ,south ,dakota as ,bennettites dacotensis1 the generic name ,cycadeoidea being adopted by ,ward#aaeh who distinguished some of ,mc,bride's specimens as ,cycadeoidea ,mc,bridei4 ,the stem is elliptical in section1 #cb cm4 long and #de cm4 in girth3 owing to the partial decay of the petiole-bases the ramental reticulum forms a prominent feature4 ,numerous flowers1 all of which are approximately at the same stage of development1 project like conical buttons above the general level of the stem-surface#aaei4 ,the bisporangiate flowers consist of a conical receptacle bearing interseminal scales and megasporophylls1 the whole being surrounded by spirally disposed bracts 7fig4 #ebi74 ,a whorl of #ah or #ai nearly mature microsporophylls is attached to the base of the receptacle 7figs4 #ebh1 #ecj72 each microsporophyll has a strong rachis extending beyond the apex of the flower-axis and bent inwards and downwards with the distal end tucked between the ascending rachis and the receptacle4 ,the slender pinnules1 in two alternate series1 are bent downwards and bear synangia in rows4 ,a transverse section just below the ovulate portion of the cone shows a continuous ring of tissue encircling the receptacle with vascular bundles parallel to the surface 7fig4 #ecj1 ,a1 m72 at a higher level the bundles fall into groups preparatory to the breaking up of the disc into separate microsporophylls4 ,immediately above the apex of the central cone the coherent basal portion of the verticil of sporophylls is replaced by the separate rachises which in section have the form of isosceles triangles 7fig4 #ecj1 ,b74 ,each microsporophyll is approximately #aj cm4 long2 the longest pinnule being #ae cm4 in length and bearing two lateral series of synangia1 #aj in each row4 ,at maturity the microsporophylls probably spread out and the whole whorl was thrown off leaving an annular rim 7fig4 #ead1 d7 such as is often seen at the base of older ovulate strobili4 ,the immaturity of the ovules in this 7fig4 #ebh7 and other specimens led to the suggestion that the strobili of ,cycadeoidea were protandrous4 ,the synangia 7fig4 #eca7 are several times broader than long and similar in size to those of the ,fern ,marattia4 ,in each synangium are two rows of elongated loculi 7fig4 #ecb7 containing oval microspores usually with a smooth exine and rather larger than those of recent ,cycads4 ,the synangium-wall is composed of a palisade-layer of thick-walled cells and a layer of smaller and thinner cells3 the palisade-layer is narrowest at the apex where dehiscence occurs and broadest at the base where the hypodermal tissue is more abundant and forms a short thick pedicel4 ,the two rows of loculi are bounded by flattened cells and there are #aj-bj loculi in each of the two rows3 dehiscence of the individual loculi occurs in the middle of the inner wall4 ,illustration3 ,fig4 #ebh4 ,cycadeoidea dacotensis4 ,longitudinal section through a bisporangiate strobilus2 s1 folded microsporophylls with synangia2 o1 receptacle bearing short megasporophylls and interseminal scales2 a1 eroded surface of bracts2 r1 ramenta between the bracts and leaf-bases2 l1 leaf-base2 c1 cortex of stem2 t1 vascular cylinder of peduncle4 7,after ,wieland2 nat4 size47 ,illustration3 ,fig4 #ebi4 ,cycadeoidea dacotensis4 ,transverse sections of a young ovulate strobilus4 ,a1 near the summit of the strobilus #b cm4 below the surface of the armour of leaf-bases1 showing numerous bracts surrounding the receptacle and embedded in a mass of ramenta1 also sections of some leaf-bases with vascular bundles4 ,b1 in this section1 #be cm4 below ,a1 the peduncle of the strobilus is seen with a cylinder of vascular bundles2 b1 a bract belonging to an adjacent strobilus4 7,after ,wieland2 nat4 size47 ,illustration3 ,fig4 #ecj4 ,cycadeoidea dacotensis4 ,transverse sections through a bisporangiate strobilus4 ,a1 showing the receptacle with its interseminal scales and ovules1 the continuous disc of microsporophylls1 m1 with vascular bundles1 and the separate 7m7 infolded portions of the microsporophylls with some synangia2 bracts and ramenta4 ,b1 this section1 cut above the apex of the receptacle1 shows the microsporophylls and synangia4 7,after ,wieland47 ,illustration3 ,fig4 #eca4 ,cycadeoidea dacotensis4 ,synangia exposed by weathering and showing the radially disposed loculi4 7,after ,wieland2 #f47 ,cycadeoidea ,marshiana ,ward4 ,illustration3 ,fig4 #ecb4 ,cycadeoidea dacotensis4 ,synangium in longitudinal section showing the thick pedicel1 the line of dehiscence1 and two loculi with a few microspores4 7,after ,wieland2 #dj47 ,this ,lower ,cretaceous ,black ,hills species#aafj affords an admirable example of a method of branching exhibited by some stems3 as shown in ,wieland's photographs#aafa there may be five or six large and massive trunks all in the same stage of fructification1 differing but little in size and forming a cluster resembling independent plants growing in close proximity to one another4 ,there is apparently no central or major axis and the habit is therefore very different from that of a branching ,bucklandia4 ,cycadeoidea ,marshiana bore large ovulate pyriform strobili projecting slightly beyond the leaf-bases2 they are #e cm4 long with a maximum diameter of #ce cm4 and have an elongated receptacle bearing short scales and sporophylls4 ,the apical bud of one of the trunks shows particularly well in transverse section the dense ramental packing between the bud-scales#aafb4 ,similar clusters of short and thick trunks occur in ,cycadeoidea superba and other ,american species4 ,in the small bisporangiate flowers of this species#aafc the microsporophylls1 #aa or #ab in the verticil1 are characterised by the presence of a ventral furrow which1 as ,wieland suggests1 may be comparable on a much simpler scale with the winged sporophylls of ,cycadeoidea colossalis 7fig4 #ecc74 ,the disc splits up at a distance of #a cm4 above the apex of the receptacle into the microsporophylls1 each of which is #ee cm4 long and bears two rows of pinnules which in the middle region have a length of #a cm42 a microsporophyll is elongate1 elliptical1 and acuminate4 ,in this species as in some others there is a brush of sterile scales at the apex of the receptacle4 ,cycadeoidea colossalis ,ward4 ,wieland#aafd has recently described some interesting features in the microsporophylls of a bisporangiate flower assigned to this ,lower ,cretaceous species from the ,black ,hills illustrating a departure from the usual type4 ,the hairy bracts extend considerably above the apex of the flower-proper2 in fig4 #ecc1 ,a1 a transverse section above the receptacle1 they are shown grouped about a circle of ,v-shaped structures1 converging towards a central point1 which are the sterile prolongations of the ten rachises of the free portions of the staminate disc4 ,each rachis is divided by a deep ventral furrow into a pair of wings 7fig4 #ecc1 ,b1 ,c71 and it is these pairs of wings that form the ,v-shaped structures in fig4 #ecc1 ,a4 ,the wings form a dome-like group above the flower-apex 7fig4 #ecc1 ,d1 ,e74 ,the synangia are borne in two rows on the concrescent disc and on the free sporophylls1 which in this type are much simpler than in other species and agree in the absence of pinnules with some forms of ,williamsonia 7cf4 fig4 #eef74 ,the receptacle is pyriform and bears very short scales and seed-stalks2 from its apex several interseminal scales are prolonged as a terminal brush1 a feature of interest in connexion with flowers of ,williamsonia4 ,wieland compares the wings of the microsporophylls to the two horns on the distal surface of the corresponding organs of ,ceratozamia and draws a comparison between them and the canopy of some ,palaeozoic seeds1 but it is doubtful whether homologies can be established between these elaborate sporophylls and the integuments of ,pteridosperm seeds#aafe4 ,cycadeoidea ,reichenbachiana 7,goeppert74 ,goeppert referred this species to his genus ,raumeria#aaff1 a generic name retained by ,carruthers though1 as ,solms-,laubach#aafg points out1 the abundance of lateral fertile shoots among the leaf-bases shows it to be essentially similar to ,cycadeoidea ,gibsoniana4 ,the type-specimen in the ,dresden ,museum is a splendid example of a fossil cycadean stem2 it is probably of ,lower ,cretaceous age1 but was found in ,galicia as an isolated specimen4 ,it consists of a portion of a cylindrical trunk similar in habit to ,c4 gigantea1 #e met4 high and about the same in diameter4 ,the pith1 according to ,schuster#aafh1 is #ac cm4 in diameter and the xylem #h cm4 broad4 ,there are many flowering shoots some of which are represented by cup-like depressions1 the base of the cup consisting of the cylindrical axis and the sides bearing the impress of the encircling bracts 7fig4 #ecd74 ,goeppert compared these lateral shoots with the buds frequently produced on the stems of ,cycas4 ,it is interesting to find that some of the cups correspond very closely in size with ,williamsonia flowers1 another indication of the very close agreement between the ,williamsonia and ,bennettites types of strobili4 ,some flowers still in place show #af bipinnate microsporophylls that were petrified before the synangium-bearing fronds unfolded#aafi4 ,the ramental scales and other tissues figured by ,schuster are of the usual type4 ,a second specimen found as a boulder in ,silesia and named by ,goeppert ,raumeria ,schulziana may1 as he suggests1 be a younger example of ,c4 ,reichenbachiana4 ,another ,galician stem1 probably also ,lower ,cretaceous in age1 is described by ,raciborski#aagj as ,cycadeoidea ,niedwiedzkii4 ,illustration3 ,fig4 #ecc4 ,cycadeoidea colossalis4 ,diagrammatic restorations of the bisporangiate flower4 ,a1 transverse section above the receptacle showing the bracts 7black71 a petiole with vascular bundles1 ramenta1 and 7#a-aj7 the wings of the microsporophylls4 ,b1 ,c1 longitudinal section of flower showing the receptacle with the small megasporophylls1 the staminate disc with winged microsporophylls and synangia1 and the terminal brush of interseminal scales 7indicated by the arrow in ,b74 ,the megasporophylls and synangia are represented larger than the actual size4 ,d1 this shows on one side the dome-like arrangement of the microsporophylls and1 on the right1 a microsporophyll in side-view4 ,e1 longitudinal section as far as the plane ,t surmounted by the apex of the collection of microsporophylls1 c2 s1 microsporophyll with synangia2 ,a1 recurved apex of microsporophyll2 ,b1 bracts2 ,d1 insertion of disc2 ,l1 outer bracts next the petiole bases4 7,after ,wieland2 ca4 nat4 size47 ,illustration3 ,fig4 #ecd4 ,cycadeoidea ,reichenbachiana4 ,cup-like cavity on the stem showing the axis and surrounding bracts of a lateral fertile shoot4 7,after ,schuster1 from a block kindly supplied by ,prof4 ,rothpletz47 ,cycadeoidea gigantea ,seward4 ,this species is founded on a large stem from the ,upper ,purbeck series of the ,isle of ,portland#aaga where it was discovered in a shaly clay #ag ft above the great ,dirt bed which yielded the trunks described by ,buckland and other authors 7fig4 #ece74 ,the stem 7fig4 #eed7 is #a met4 #ah cm4 high and has a maximum diameter of #a met4 #g cm4 ,it is the tallest fossil ,cycadean stem so far found in a single piece though ,cycadeoidea ,jenneyana probably reached a greater height4 ,the stem is elliptical in section 7fig4 #ecg71 a form due in part at least to compression4 ,the only tissues preserved are in the superficial region of the persistent leaf-bases4 ,as the result of decay before mineralisation many of the petiole-bases are represented by cavities or meshes in a prominent reticulum of silicified ramental scales4 ,towards the apex the leaf-bases are smaller and a conical bud surrounded by linear scale-leaves occupies the summit3 an irregular cap of ramental scales forms the apex of the terminal bud4 ,in section the bud would no doubt present an appearance like that shown in ,wieland's photograph of the terminal cone of ,c4 ,marshiana#aagb4 ,there is a striking resemblance both in the ramental cap and in the form of the protective scales between the fossil stem and such a ,cycad as ,encephalartos ,altensteinii#aagc4 ,a remarkable feature of ,c4 gigantea is the absence of any fertile shoots among the leaf-bases4 ,in one tangential section a small bud was found1 but it affords no evidence of the presence of any reproductive organs4 ,a similar bud is described by ,lignier#aagd in the stem of ,c4 micromyela4 ,the absence of lateral flowers is1 however1 hardly a sufficient reason for separating this stem generically from other species of ,cycadeoidea3 negative evidence in this case is of doubtful value4 ,while it is possible that the strobili were terminal as in most recent ,cycads1 it is more probable that they were lateral4 ,the surface-features1 though not perfect1 are for the most part sufficiently well preserved to enable one to recognise the bract-encircled axes of strobili were any present4 ,if as ,wieland believes1 and he is probably correct1 the production of flowers was the culminating event in the life of these ,cycadean plants1 the absence of fertile shoots is merely an expression of immaturity4 ,it is1 however1 difficult to understand how lateral branches could find their way to the surface among the crowded and cork-covered leaf-bases of the stem4 ,the absence of flowers may be due to some unfavourable external conditions4 ,the petioles consist of parenchymatous ground-tissue with many secretory sacs and in some cases twelve partially preserved vascular bundles3 the xylem consists of radial rows of centrifugal tracheids and medullary rays1 but it is not possible to say whether any centripetal xylem was present4 ,a fairly thick band of phelloderm and periderm1 apparently subepidermal in origin1 forms the peripheral tissue1 and in places epidermal cells with attached ramenta are clearly preserved4 ,the ramenta are of the type characteristic of the majority of fossil ,cycadean stems4 ,stomata were found showing a pair of guard-cells and apparently two subsidiary cells3 the epidermal cells have straight walls4 ,illustration3 ,fig4 #ece4 ,section of the quarry in the ,isle of ,portland in which ,cycadeoidea gigantea was found4 ,illustration3 ,fig4 #ecf4 ,cycadeoidea gigantea4 7,the original is in the ,british ,museum2 nat4 size47 ,illustration3 ,fig4 #ecg4 ,cycadeoidea gigantea4 ,transverse section of the stem4 ,illustration3 ,fig4 #ech4 ,cycadeoidea micromyela4 ,a1 tracheids from the stele4 ,b1 course of the vascular bundles at the base of a leaf4 ,c1 section of a leaf-trace entering the stele2 m1 l1 median and lateral lobes of the trace4 7,after ,lignier47 ,cycadeoidea micromyela ,morire4 ,this ,liassic species from ,normandy has been fully investigated by ,lignier#aage2 originally referred to the ,conifers1 it was afterwards described by ,morire#aagf as ,cycadeoidea micromyela4 ,as regards external features the stem is of the usual ,cycadeoidea type3 ,saporta#aagg assigned it to the genus ,platylepis4 ,the secondary xylem consists of tracheids with bordered pits on the radial walls arranged as single contiguous rows1 resembling scalariform pitting1 or as #a-b rows of separate circular pits 7fig4 #ech1 ,a71 a type different from that of the great majority of ,mesozoic species4 ,the uniseriate medullary rays are #g-bj cells deep1 a character recalling the compact wood of ,indian ,williamsonia stems4 ,ramental scales are for the most part replaced by long unicellular hairs like those of ,williamsonia scotica and some ,indian stems4 ,lignier states that true ramenta occur on the young leaves and in older fronds become transformed by separation of the cells into long tubes4 ,each leaf-trace arises as a single bundle dividing into three as it leaves the stele and eventually splits up into several collateral bundles 7fig4 #ech1 ,b1 ,c74 ,the stele is elliptical4 ,no fertile shoots are preserved3 a single axillary bud is described which agrees very closely with that in ,cycadeoidea gigantea4 ,illustration3 ,fig4 #eci4 ,cycadeoidea ,jenneyana 7874 ,longitudinal section of an ovulate strobilus1 showing the pyriform receptacle with vascular supply1 the long interseminal scales and megasporophylls1 and a few of the surrounding bracts4 7,after ,wieland2 #a nat4 size47 ,cycadeoidea ,jenneyana ,ward4 ,the stems of this species1 from the ,black ,hills of ,dakota#aagh1 resemble those of ,cycadeoidea gigantea and ,c4 ,reichenbachiana in their thick columnar form but differ from the former in the presence of bisporangiate flowers associated with the leaf-bases4 ,this species probably reached a length of #c-d met4 ,a striking feature#aagi is the unusual thickness of the xylem-cylinder1 which shows clear indications of concentric rings1 probably the expression of seasonal changes during the production of secondary conducting tissue by a single cambium4 ,similar concentric rings have been described in the stems of the recent ,cycad ,dioon spinulosum#aahj4 ,fig4 #eci represents an ovulate strobilus referred to this species by ,wieland4 ,cycadeoidea pumila ,fliche and ,zeiller4 ,this ,french ,portlandian species#aaha affords a good example of a very small bulbiform trunk1 #ce-d by #be-c cm41 superficially resembling a ,pine-cone3 the leaf-bases are1 however1 less uniform in size and shape than ,abietineous cone-scales2 there are also indications of interpetiolar ramenta and a small lateral1 presumably fertile1 branch4 ,a stem of similar form is described by ,saporta#aahb from ,corallian beds in ,france as ,bulbopodium micromerum1 and ,cycadeoidea nana ,ward#aahc from ,dakota is another example of a small ,zamia-like ,mesozoic stem4 ,a small tuberous stem1 #h #ge cm41 was described by ,lindley and ,button from ,lyme ,regis as ,cycadeoidea pygmaea#aahd2 no flowers are shown in the drawing1 but occasional irregularities in the arrangement of the leaf-bases may be due to the presence of lateral fertile shoots4 ,cycadella4 ,ward4 ,this generic name was instituted by ,lester ,ward#aahe for some petrified stems from ,jurassic beds in ,wyoming of relatively small size1 bulbous or more or less spherical1 and characterised by the presence of a thick layer 7#e-ae mm47 of dense ramental tissue4 ,the unusually vigorous development of the ramental scales is an interesting feature1 though it is perhaps questionable whether it is worthy of generic recognition4 ,the flowers of ,cycadella1 though less than those of most ,cycadeoidea stems1 are of the same type4 ,in a later account of the genus ,ward#aahf describes a few additional species and in ,cycadella ramentosa he notes the preservation of young fronds4 ,the fronds are small and bear a few pinnae3 the xylem is said by ,wieland#aahg to be mesarch1 but in the absence of more details the foliar bundles cannot be fully described4 ,in some ,cycadellas young flowers1 less than #a cm4 in diameter1 are preserved1 those of ,cycadella wyomingensis 7#g mm4 in diameter7 being the smallest bisporangiate strobili so far recorded4 ,the ,french species1 ,cycadeoidea micromyela ,mor41 resembles ,cycadella in the profuse development of ramental tissue which may cover the surface of the stem4 ,amphibennettites4 ,fliche4 ,this generic name was instituted#aahh for two species founded on very imperfectly preserved #8fruits' of ,lower ,cretaceous 7,albian7 age from the ,argonne which1 though in close agreement with ,bennettites as represented by ,b4 ,gibsonianus and ,b4 ,morierei1 are referred to a separate genus on the ground that the preservation is not such as to establish their generic identity with those species and because of certain distinctive features4 ,amphibennettites ,bleicheri ,fliche4 ,the ovulate strobili are sub-elliptical1 #ce #c cm41 with several elliptical pits close to the surface originally occupied by seeds borne on short stalks and larger than the seeds of other species of ,cycadeoidea 7,bennettites74 ,interseminal scales occur between the seeds4 ,the second species1 ,amphibennettites ,renaulti1 is rather larger and more conical3 the seeds reach a length of #aa mm4 greater than that of any of the ,american seeds described by ,wieland4 ,in neither species is there any indication of an involucre of bracts4 ,the preservation of the specimens leaves much to be desired1 but it would seem that the ,argonne fossils agree in their main characters with ,bennettitean strobili and it is doubtful whether a distinctive generic name is necessary4 ,the occurrence of seeds over the whole surface1 a feature that suggested the name ,amphibennettites1 may be only apparent and the result of cutting the cone transversely4 ,it is worthy of note that one of ,fliche's sections#aahi bears a close resemblance to an ,araucarian cone1 and in the absence of structure the two types of cone might easily be confused4 ,illustration3 ,fig4 #edj4 ,vectia luccombensis4 ,transverse section showing the alternation of fibres1 s1 s1 and radial pairs of pitted elements1 v and v2 m1 medullary-ray cells2 a1 parenchyma cell between four thin-walled elements2 sp1 pits between adjacent fibres2 l1 much reduced lumen of fibre4 7,after ,stopes47 ,vectia4 ,stopes4 ,genus incertae sedis4 ,vectia luccombensis ,stopes4 ,the generic name ,vectia has been given by ,dr ,stopes#aaij to some petrified secondary phloem discovered by her at ,luccomb ,chine in the ,isle of ,wight3 the fossil is from ,aptian beds4 ,the mass of phloem is #bf mm4 in breadth and consists of regularly alternating bands of thin-walled sieve-tubes and very thick fibres associated with a little parenchyma 7fig4 #edj74 ,to the naked eye the specimen presents an appearance suggestive of rings of growth but this is due to the presence of bands of #b-c narrow cells which are probably cork4 ,the whole is penetrated by uniseriate medullary rays4 ,a striking feature is the regular alternation of single rows of fibres with two bands of sieve-tubes2 in places the two bands of sieve-tubes are separated by #b-d rows of very flat1 presumably1 cork-cells1 and similar bands may be adjacent to or pass obliquely across the fibres4 ,the elongated elements described as sieve-tubes1 though thin in comparison with the fibres1 have thickened walls and on their radial faces are single rows of circular pits1 often in pairs2 these are almost certainly sieve-areas which have lost the finer pitting of the sieve-plates4 ,the fibres are more or less square in transverse section and have excessively thick walls1 the lumen being reduced to a small hole4 ,parenchymatous cells 7fig4 #edj1 a7 occupy the angles between the sieve-tubes and occasionally stretch tangentially between a pair of tubes3 these are compared by ,dr ,stopes to companion-cells1 but their manner of occurrence hardly justifies the interesting suggestion that they may be precursors of the ,angiosperm companion-cells4 ,the medullary rays may be as wide as the elements which they traverse2 they are characterised by their wavy walls1 as seen in radial longitudinal sections2 no pitting was noticed4 ,a remarkable feature of the specimen is its considerable breadth3 it is pointed out that in a giant stem of ,sequoia with a girth of over #dj ft the secondary phloem does not exceed #c-d mm4 in breadth4 ,the great thickness of the phloem in the fossil suggests comparison with the corresponding tissue in recent and fossil ,cycadean stems1 and the alternation of hard and soft phloem is a feature exhibited also by ,cycadeoidea ,gibsoniana 7fig4 #eah1 ,b74 ,dr ,stopes concludes that the phloem is in the main similar to that in some ,cupressineae1 ,taxineae1 and ,taxodineae4 ,it is noteworthy that similar phloem with sieve-tubes and fibres associated with cork is described by ,graf ,solms-,laubach#aaia from ,upper ,jurassic beds in ,franz ,josef ,land4 ,the systematic position of ,vectia cannot be definitely determined1 but ,i believe that it is more closely allied to ,cycadean than to ,coniferous phloem4 99 99 99 99 99 ,note4 ,it is unfortunate that ,mr ,wieland's second volume dealing with ,american ,cycads ,wieland 7#af7 did not come into my hands until nearly the whole of this volume was in type4 ,students will find in it many additions to our knowledge of ,cycadeoidea and ,williamsonia1 much theoretical discussion that is suggestive and interesting1 useful summaries of our knowledge of fossil ,cycads1 and many beautiful photographic plates illustrating the morphology of ,american species of ,cycadeoidea4 ,,chapter ,,xxxvii4 ,,bennettitales 7continued74 ,,williamsonia4 ,carruthers4 ,this genus was first figured by ,young and ,bird#aaib from specimens obtained from ,lower ,estuarine beds near ,whitby3 these authors compared the fossils to the head of an ,artichoke 7,cynara integrifolia71 #8the covering or calyx consisting of numerous lanceolate and striated leaves' 7fig4 #edd74 ,in #ahdj ,williamson#aaic noticed the association with fronds of ,zamia gigas ,lind4 and ,hutt4 of #8a remarkable fossil1 apparently connected with the fructification of a ,cycas1' and some years later ,yates#aaid expressed the opinion that the fructifications figured by ,young and ,bird probably belonged to the plants which bore the fronds known as ,zamites gigas4 ,leckenby#aaie figured some leaves of ,palaeozamia pecten 7 ,ptilophyllum pecten7 in close association with a small flower of ,williamsonia which was subsequently recognised as a whorl of microsporophylls4 ,in #ahgj two papers of exceptional interest were published1 one by ,williamson#aaif who was the first to attempt an exhaustive account of the genus1 and the other by ,carruthers#aaig who proposed the name ,williamsonia1 thus associating #8with a group of the most characteristic ,yorkshire fossils two men 7father and son7 who have largely contributed to the exposition of ,yorkshire geology4' ,carruthers instituted a new tribe ,williamsonieae for the genus ,williamsonia1 the type-species being ,williamsonia gigas3 the specific name had been previously given by ,lindley and ,hutton to the fronds 7,zamia gigas7 of the plant which was believed to have borne the flowers for which the new designation was proposed4 ,two other species1 ,williamsonia hastula and ,w4 pecten1 were assigned to the new genus4 ,the conclusion arrived at by ,williamson as to a connexion between ,zamites gigas and ,williamsonia flowers was1 however1 not accepted by ,saporta#aaih1 who figured and described several exceptionally good specimens from the ,yorkshire coast which formed part of the ,yates collection in the ,paris ,natural ,history ,museum4 ,in #ahig a short account was published#aaii of the ,yates specimens1 an examination of which convinced me of the correctness of ,williamson's views as to an organic connexion between stems1 peduncles1 flowers1 and fronds4 ,during a visit to ,paris several photographs were taken1 but these were not published3 similar photographs have since been reproduced by ,wieland#abjj and reduced copies from two negatives in my possession are shown in figs4 #eda1 #edb4 ,the restoration by ,williamson in his well-known memoir is probably correct so far as the general habit of the plant is concerned1 though the flowers which he speaks of as male are now known to be ovulate4 ,the position of the male organs1 whether borne separately or on the same axis as the megasporophylls1 has not been definitely settled4 ,in #ahia the ,marquis of ,saporta thus introduced his discussion on ,williamsonia1--#8avec les ,williamsonia nous abordons un des problmes les plus difficiles1 un des sujets des plus controverss1 mais aussi les plus curieux1 peut-tre mme le plus remarquable de tous ceux que nous offre l'ensemble des plantes jurassiques4' ,wieland's investigations have placed us in possession of many important facts with regard to the closely allied flowers of ,cycadeoidea and have enabled us considerably to extend our knowledge beyond the stage represented by the work of ,carruthers1 ,williamson1 and other authors2 and more recently ,nathorst's important discoveries have demonstrated the close agreement between ,williamsonia and ,bennettites 7,cycadeoidea74 ,several problems still remain unsolved4 ,having regard to the deficiency of the data concerning the morphology of the ,williamsonia type of flower and the wider question as to a phylogenetic relationship that some botanists believe to exist between the ,bennettitales and the ,angiosperms1 ,saporta's words are still pertinent4 ,wieland's discoveries in ,mexico#abja have furnished additional evidence of the wide geographical distribution of the ,williamsonia type of flower in the ,jurassic period1 and it may be confidently asserted that the ,bennettitales1 including both ,williamsonia and ,cycadeoidea1 occupied a dominant position in the floras of the world during the stage of plant-development immediately preceding the evolution and rapid spread of the ,angiosperms1 the present dominant class4 ,there has been considerable uncertainty among authors with regard to the application of the name ,williamsonia4 ,in former accounts of the genus the name was employed by me both for leaves and flowers on the ground that ,williamson was correct in his opinion as to the connexion between ,williamsonia gigas and ,zamites gigas4 ,the type of frond to which the latter term is applied is by no means uncommon in ,jurassic strata though it is not always associated with flowers1 and the use of the generic term ,williamsonia is therefore not invariably justifiable4 ,nathorst#abjb has recently reiterated his opinion that it is inadvisable to employ the name ,williamsonia except for the flowers or the complete plant and strongly urges palaeobotanists to retain the provisional genus ,zamites when the fronds only are in question4 ,while agreeing with the contention that the greatest care should be exercised to avoid the use of generic names implying a correlation of vegetative and reproductive organs that rests on any evidence short of demonstration1 it may be suggested that the better plan is to add the name ,williamsonia in parentheses after ,zamites or ,ptilophyllum in cases where there is no reason to doubt that the fronds belong to a ,williamsonia plant4 ,williamsonia gigas 7,williamson74 ,the species selected for a rather detailed description is still imperfectly known1 but it is particularly interesting as the type on which the first scientific account of the genus was based4 ,the name ,williamsonia gigas is now generally employed for the flowers which bore megasporophylls as the essential organs3 they may have been bisporangiate1--a view that seems to me the more probable1--but this has not been demonstrated4 ,there are very few cases in which fronds of ,zamites gigas occur in organic connexion with stems1 and we cannot with safety employ other than a provisional generic term for fossil stems which it is believed bore flowers of the ,williamsonia type4 ,for the imperfectly preserved piece of stem shown in fig4 #eda the name ,williamsonia 7,bucklandia7 gigas is employed1 as there is no reasonable doubt that in addition to the fronds of ,zamites gigas it bore peduncles 7fig4 #eda1 a71 with ,williamsonia flowers4 ,this and other stems found in close association with ,williamsonia flowers in ,england1 ,india1 and ,mexico are of the type known as ,bucklandia#abjc2 but it would in most instances be unwise to add ,williamsonia even as a subordinate title4 ,casts of stems in close association with fronds and flowers are not uncommon in collections of plants from the ,yorkshire coast2 the surface-features are of the type shown in fig4 #egf1 rhomboidal or lozenge-shaped bases of petioles as described under the genus ,bucklandia#abjd4 ,the stem reproduced in fig4 #eda1 about #e cm4 broad1 is imperfectly preserved and the leaf-bases are not clearly seen4 ,saporta's figure#abje conveys but a poor idea of the actual specimen4 ,to one side of the stem1 #e cm4 from the lower1 broken1 end1 are attached the petioles of two clearly preserved fronds of ,zamites gigas1 and above these is part of a third frond apparently in its original position4 ,the main axis is prolonged obliquely upwards to the left as a branch1 a1 #c cm4 broad and #ad cm4 long1 covered with hairy bracts and bearing distally several narrow1 linear-lanceolate1 scale-leaves4 ,this branch is undoubtedly a fertile shoot or peduncle4 ,a specimen figured 7from a drawing7 by ,saporta#abjf as a peduncle of a ,williamsonia flower and reproduced in fig4 #edb is1 in surface-features1 identical with the branch a shown in fig4 #eda1 but at the apex it bears a bud covered with linear bracts identical with those of ,williamsonia gigas4 ,this bud is almost certainly a young flower4 ,similar peduncles are described by ,williamson1 and he speaks of one which is bifurcated3 this specimen is probably that reproduced in fig4 #edc and now in the ,leeds ,museum3 at the base the axis is #ce cm4 in diameter2 the two divergent arms bear numerous bracts identical with those of ,williamsonia gigas and in addition are a few shorter ovate scales recalling those figured by ,nathorst as probably belonging to ,williamsonia pecten4 ,the ,leeds specimen is from the ,lower sandstone and shale near ,scarborough4 ,similar branched peduncles are represented in the ,whitby ,museum and in the ,national ,collection4 ,wieland#abjg has also figured a peduncle bearing a #8typical fruit bud' of ,williamsonia gigas similar to that reproduced in fig4 #edb4 ,these specimens fully justify ,williamson's restoration published in his paper of #ahgj4 ,illustration3 ,fig4 #eda4 ,williamsonia gigas4 ,fronds 7,zamites gigas7 and flowering shoot1 a1 attached to a stem 7,bucklandia74 7,yates ,collection1 ,paris2 nat4 size47 ,illustration3 ,fig4 #edb4 ,williamsonia gigas4 ,flowering shoot and flower-bud4 7,yates ,collection1 ,paris47 ,in a former account of this species#abjh the opinion was expressed that the flowers described by ,williamson as male were ovulate and constructed on the plan of those of ,bennettites ,gibsonianus ,carr4 ,this conclusion has since been confirmed by ,nathorst#abji who succeeded in obtaining excellent preparations of the cuticular membranes of interseminal scales and micropylar tubes 7fig4 #ede71 demonstrating their very close agreement with those of the flowers of ,cycadeoidea4 ,illustration3 ,fig4 #edc4 ,williamsonia gigas4 ,two peduncles1 ,b and ,c1 with imperfectly preserved bracts4 ,diameter of axis1 ,a1 #ce cm4 7,from a specimen in the ,leeds ,museum2 nat4 size47 ,one of ,williamson's #8carpellary discs' has been shown by ,nathorst to be a verticil of microsporophylls bearing synangia1 but both this author and ,lignier#abaj think that the two specimens figured by ,williamson as carpellary discs are distinct organs1 one being a staminate whorl and the other a sterile infundibuliform organ4 ,my own view is that both are of the same nature and consist of microsporophylls4 ,illustration3 ,fig4 #edd4 ,williamsonia gigas4 ,portion of a flower showing the protective bracts1 the annular zone formed by numerous sterile sporophylls and interseminal scales1 and the large central cavity originally occupied by the receptacle4 7,from a specimen in the ,williamson collection1 ,cambridge ,botany ,school2 nat4 size47 ,illustration3 ,fig4 #ede4 ,williamsonia gigas4 ,micropylar tube4 7,after ,nathorst47 ,fig4 #edd represents the usual form in which the flowers of ,w4 gigas are found2 it consists of linear bracts covered with hairs identical with those on the peduncles shown in figs4 #eda-edc2 they surround a pyriform axis and form what ,williamson called an involucrum4 ,the base of the fossil is characterised by an annular zone formed of crowded1 radially disposed1 narrow ridges now known to be casts of interseminal scales4 ,at the outer edge of this annular area impressions of the peltate ends of interseminal scales are not infrequently preserved4 ,fig4 #ede is a photograph of one of ,nathorst's preparations showing the very great similarity between a micropylar tube of ,w4 gigas and the corresponding structures in ,cycadeoidea4 ,the small micropylar tubes are surrounded by #e-f polygonal expanded apices of interseminal scales as in ,cycadeoidea 7fig4 #eae2 cf4 also fig4 #efc71 and the apex of each peltate distal end projects slightly as a central papilla composed of more strongly cuticularised cells4 ,in most specimens the megasporophylls and interseminal scales 7sterile megasporophylls7 are preserved only as an annular zone at the base of the receptacle 7fig4 #edh1 as71 but it is clear from some specimens of ,w4 gigas and other species figured by ,saporta#abaa1 ,nathorst#abab1 and ,krasser#abac that originally the whole surface of the pyriform axis was beset with these organs which fell off1 presumably1 when the seeds had reached maturity4 ,no satisfactory examples of seeds have been found in ,english specimens4 ,krasser has described some specimens of ,williamsonia from ,jurassic rocks in ,sardinia to which he assigns some associated seeds1 but1 as he admits1 there is no proof of any connexion4 ,in some cases a funnel-like depression is seen at the upper end of a strobilus of ,w4 gigas 7fig4 #edf1 ,b1 ,c1 a7 identical in the occurrence of radially disposed ridges with the annular zone at the base and due to the preservation of interseminal scales and aborted megasporophylls in the upper part of the receptacle3 in this region also the impressions of polygonal apices of the scales are sometimes found4 ,the probability is that while the greater part of the armour of scales and seeds was thrown off1 at the upper and lower end of the receptacle some sterile megasporophylls and scales remained 7fig4 #edh1 as1 dl74 ,illustration3 ,fig4 #edf4 ,williamsonia gigas4 ,a1 apical portion of flower4 ,b1 cast of ,a2 a1 persistent interseminal scales4 ,c1 flower in longitudinal section4 ,c1 interseminal scales from the base4 7,williamson ,collection1 ,botany ,school1 ,cambridge47 ,williamson regarded the funnel-shaped depression as the impression of the lower surface of a laterally expanded portion of the axis of the flower1 and to this expansion he gave the name lenticular disc 7figs4 #edf1 #edg1 a74 ,it is1 however1 much more likely that the apparent extension of the axis is due to the preservation of the sterile zone of armour which formed a cluster of appendages1 the impressions of which are seen on the sides of the funnel-like depression1 the receptacle being prolonged as a slender axis 7fig4 #edg1 ,c74 ,the next point to consider is the form of the axis beyond the level of the collar of sterile armour4 ,williamson described the axis as spreading out to form the lenticular disc and then prolonged as a narrow conical pyramidal axis which is slightly extended horizontally immediately below a terminal mammilla3 the apical mammilla he designated the corona 7fig4 #edg1 ,c1 r74 ,as already stated1 the lenticular disc is probably not an expanded part of the axis but the result of the preservation of a spreading mop-like cluster of interseminal scales4 ,this is the view expressed by ,lignier#abad who kindly furnished the block from which fig4 #edh is reproduced4 ,the lower face of ,williamson's lenticular disc is characterised by a series of spoke-like radiating ridges 7fig4 #edg1 ,a7 between which are less distinct radially disposed lines1 and at the periphery there are impressions 7fig4 #edg1 ,a71 continuous with some of the radiating ridges1 of the terminal shields of interseminal scales4 ,in fig4 #edg1 drawn from one of the original specimens described by ,williamson1 these features are shown at ,a and ,b3 fig4 ,a represents the circular area1 which is at right-angles to the axis of the flower1 in surface-view4 ,in the centre of this circular area is a depression ending in a short papilla surrounded by a narrow basal rim3 this feature is shown on a cast of the specimen represented in fig4 #edg1 ,b4 ,in this case ,williamson's corona is seated on a very short axis whereas in fig4 #edg1 ,c1 also from one of ,williamson's specimens1 the corona forms the apex of a longer pyramidal axis4 ,wieland#abae regarded the circular area seen in fig4 #edg1 ,a1 as the impression of the apical portion of a bisporangiate strobilus1 the ridges marking the edges of the incurved distal portions of microsporophylls bent over the apex of the ovulate cone 7cf4 fig4 #eac71 and he interpreted the polygonal depressions at the periphery 7fig4 #edg1 ,a7 as those of sori1 an interpretation entirely different from that of ,lignier4 ,the latter author#abaf in part reasserted his opinion but modified it as regards the meaning of the ridges on the circular area1 agreeing so far with ,wieland as to consider them as having been formed by the folded-over rachises of microsporophylls attached as a concrescent collar to the base of the ovulate cone4 ,this interpretation does not1 however1 explain the relation between the radial striations on the circular area and the polygonal impressions at its periphery4 ,wieland still dissents from ,lignier's opinion and suggests that the circular area has not been demonstrated to belong to the apical end of a flower4 ,fig4 #edg shows that its position is apical4 ,fig4 #edh represents ,lignier's view as to the nature of the rim surrounding the apical mammilla3 he suggested that several interseminal scales borne at the apical region of the receptacle were concrescent and formed linear bracts the edges of which are represented by the main ridges in fig4 #edg1 ,a4 ,these concrescent scales bent upwards and were closely applied to or perhaps concrescent with the pyramidal axis and were then prolonged as a wide infundibuliform apparatus 7,williamson's carpellary disc74 ,this organ was1 however1 easily detached1 and the rim seen at r in fig4 #edg1 ,c1 represents its narrow broken base4 ,with this view ,i am in general agreement2 but while ,lignier regards the funnel-like appendage as sterile and considers that similar organs1 but with a large central cavity at the base of the funnel1 may have been microsporophyll-discs which were borne below the ovulate strobilus in the position occupied by the microsporophylls in ,cycadeoidea 7fig4 #ebh7--my inclination is to see in the terminal appendage a whorl of concrescent microsporophylls4 ,this view lacks the support of demonstration4 ,it is obvious from ,williamson's specimens and from others described by ,saporta1 ,nathorst1 and ,lignier that the receptacle of ,williamsonia gigas was not so simple in its termination as that of the flowers of ,cycadeoidea4 ,in ,cycadeoidea dacotensis ,wieland showed that the apex of the receptacle bore a tuft of long interseminal scales1 and it is readily conceivable that these apical appendages were still further developed in some ,williamsonia flowers to form a whorl of concrescent leaves borne on the prolonged apex of the axis4 ,there is little doubt as to the homology of interseminal scales and microsporophylls1 and there is no difficulty in supposing that while in some flowers the foliar organs assumed the form of interseminal scales of unusual length1 in other species they became microsporophylls4 ,illustration3 ,fig4 #edg4 ,williamsonia gigas4 ,a1 flower in longitudinal section1 showing1 especially on the left side1 interseminal scales and megasporophylls and a pyriform cavity representing the central axis 7nat4 size74 ,a1 the under surface of the apical region4 ,a1 interseminal scales from ,a4 ,b1 cast of ,a4 ,c1 apical region of another specimen2 a1 interseminal scales2 c1 column2 r1 ridge4 7,williamson ,collection1 ,botany ,school1 ,cambridge47 ,illustration3 ,fig4 #edh4 ,williamsonia gigas4 ,restoration showing an ovulate strobilus bearing a terminal infundibuliform appendage4 ,lignier1 to whom the restoration is due1 points out that the apical portion of the axis at dl should be represented as straight and not1 as in the figure1 horizontally expanded4 bi1 bracts2 as1 persistent interseminal scales forming the annular zone2 r1 receptacle2 cs1 caducous megasporophylls and interseminal scales2 dl1 persistent interseminal scales1 an extension of which formed the large funnel-like appendage1 at2 ap1 apex of the receptacle4 7,after ,lignier47 ,it is noteworthy that the radiating ridges on the circular area shown in fig4 #edg1 ,a1 agree in position and approximately at least in number with those on the sides of the cupular disc of the microsporophyll-verticil of ,williamsonia whitbiensis#abag4 ,nathorst describes a specimen seen in a private collection in which an infundibuliform appendage appeared to be preserved in situ at the apex of a flower of ,williamsonia gigas 7cf4 fig4 #edh1 at74 ,thomas#abah1 in his description of ,williamsoniella1 compares the radial ridges on the apical sterile portion of a flower of ,williamsonia gigas to the ridges on his ,williamsoniella which are formed by the tips of infolded microsporophylls4 ,illustration3 ,fig4 #edi4 ,williamsonia gigas4 ,a1 diagrammatic drawing showing the position of the synangia1 at ,s1 and part of the staminate disc4 ,b1 a single synangium2 #f4 7,after ,thomas47 ,williamsonia gigas 7,microsporophylls74 ,illustration3 ,fig4 #eej4 ,williamsonia gigas4 ,side-view of an incomplete staminate disc showing the basal cup torn at the lower end and part of one of the free microsporophylls4 7,diagrammatic drawing1 after ,thomas2 nat4 size47 ,in the course of an examination of the ,williamsonia specimens 7from ,yorkshire7 in ,paris in ,july of last year 7#aiad7 ,mr ,thomas#abai found a specimen previously overlooked1 which is undoubtedly either a male flower or1 as ,i am inclined to think1 the staminate disc of a bisporangiate flower of ,williamsonia gigas4 ,the nature of the matrix shows that it came from the neighbourhood of ,whitby4 ,it consists of an urn-shaped organ formed of the concrescent bases of #ah-bj microsporophylls each #g-h mm4 wide2 the cup is #e-f cm4 broad1 the base being torn but tapered 7fig4 #edi7 as though originally prolonged downwards into a stalk as in ,w4 spectabilis4 ,along the middle line of each sporophyll is a series of depressions1 probably the same in nature as those on ,w4 whitbiensis described by ,nathorst1 though it is not clear whether1 in this case at least1 they represent aborted synangia4 ,some reniform synangia 7fig4 #edi1 ,b7 occur in the rock just above the cup4 ,the sporophylls spread outwards from the base and then curve inwards1 bending outwards again as they become free4 ,a portion of a microsporophyll is shown in fig4 #eej bearing segments projecting inwards as in ,w4 spectabilis 7fig4 #eea74 ,this specimen1 which occurs in association with female flowers1 is regarded by ,mr ,thomas as part of a unisexual flower4 ,he discusses the possibility of its connexion with an ovulate receptacle and expresses the opinion that if it were borne at the upper end of a bisporangiate flower the whole would be top-heavy and the arrangement uneconomical4 ,on the other hand if1 as suggested on page #dcd1 the flowers were bisexual the staminate disc1 which reached maturity before the ovules1 may have been thrown off1 as in ,cycadeoidea1 before the seeds were ripe4 ,the form of the disc resembles that of the ,indian specimen described on another page as ,williamsonia sp41 cf4 ,w4 setosa ,nath42 it does not1 ,i venture to think1 afford an argument against the view that the microsporophyll-cup of some ,williamsonia flowers was attached near the apex of the receptacle and was formed of modified foliar organs homologous with those which1 in the ovulate portion of the flower1 constitute the interseminal scales and megasporophylls4 ,a further consideration of the microsporophylls of ,williamsonia will be found in a later section of this chapter4 ,williamsonia spectabilis ,nathorst4 ,this species#abbj1 the first example of undoubted microspore-bearing organs referred to ,williamsonia1 was founded on material discovered by ,prof4 ,nathorst in the ,lower ,estuarine series of ,whitby2 it has also been obtained from beds of the same age at ,marske in the ,cleveland district of ,yorkshire#abba4 ,williamsonia spectabilis1 though indubitably a male organ1 has not been found attached to a stem1 and there is no decisive evidence as to its connexion with a particular species of frond4 ,nathorst believes that it belongs to the plant which bore the leaves known as ,ptilophyllum pecten1 an opinion based chiefly on association4 ,the more complete specimens consist of a broad funnel-shaped organ prolonged below into a slender stalk and divided at the margin into several linear-lanceolate segments 7microsporophylls7 the apices of which were rolled inwards like young fern-fronds 7figs4 #eea1 #eeb74 ,the synangia agree closely in form and in such structural features as can be made out from cuticular preparations with those described by ,wieland in ,american species of ,cycadeoidea2 they are slightly reniform1 #e-f mm4 long and #b mm4 broad and divided into several loculi by transverse partitions 7fig4 #eeb74 ,the microspores1 #eh-fe in length1 are rather narrow1 ovate and very similar to those described by ,solms-,laubach#abbb in ,cycadeoidea etrusca4 ,the synangia are attached in two rows to slender lateral segments which appear to be given off from the upper face near the median line of the broad linear sporophylls 7fig4 #efe1 ,a74 ,nathorst points out that the position of the fertile pinnae brings the sporophylls into close relation with the vegetative fronds of ,ptilophyllum pecten and other ,cycadean fronds in which the pinnae are attached to the upper face of the rachis4 ,while the longer pinnae in the middle portion of a sporophyll bear several synangia1 those near the base and apex are shorter and1 in the proximal region nearer the broad cup formed by the coherent bases of the sporophylls1 occur singly1 thus approaching the condition characteristic of ,w4 whitbiensis 7fig4 #efe1 ,b7 in which they are sessile on the simple microsporophylls4 ,it is noteworthy that in some specimens figured by ,nathorst there is a tendency of the lower part of the cup to break away from the coherent bases of the sporophylls 7fig4 #eea7abbc1 and it is not unlikely that some of the impressions described as infundibuliform appendages are incomplete examples of ,williamsonia spectabilis4 ,illustration3 ,fig4 #eea4 ,williamsonia spectabilis and leaves of ,ptilophyllum pecten4 7,after ,nathorst2 nat4 size47 ,illustration3 ,fig4 #eeb4 ,williamsonia spectabilis4 ,restoration of an almost mature male flower4 7,after ,thomas2 approximately nat4 size47 ,illustration3 ,fig4 #eec4 ,williamsonia ,leckenbyi4 ,surface-view and in section4 7,restoration after ,nathorst47 ,williamsonia ,leckenbyi ,nathorst4 ,this species1 founded on specimens from the ,middle ,estuarine beds exposed on the ,yorkshire coast at ,cloughton ,wyke#abbd1 is characterised by the almost spherical form of the strobilus1 #de-e cm4 in diameter4 ,the relatively small receptacle is covered by a thick mass of megasporophylls and interseminal scales except in the lower part which bears only sterile scales4 ,nathorst believes that the seeds were very small1 but no undoubted examples have been found4 ,a specimen in the ,british ,museum1 figured in #aijjabbe1 shows the surface-view of an impression of the base of the flower2 a small circular raised boss occupies the centre--the scar of the receptacle--and surrounding this is a reticulum formed by the impression of the distal ends of the interseminal scales4 ,the uniform nature of the reticulum1 the meshes of which are all of the same type1 shows that in the basal region of the flower the organs borne on the receptacle were all sterile as in ,cycadeoidea 7,bennettites7 ,morierei4 ,except in the smaller diameter of the receptacle this specimen is practically identical with that of ,williamsonia ,carruthersi ,sew4 reproduced in fig4 #eei4 ,the form of the strobilus is shown in ,nathorst's restoration#abbf represented in fig4 #eec4 ,the interseminal scales have broad peltate distal ends characterised by a patch of lighter and thinner-walled cells at the apex 7fig4 #eed72 the micropylar tubes are slightly expanded at the summit and their epidermal cells are papillose as in ,williamsonia scotica 7cf4 fig4 #efc1 ,b74 ,nathorst in #aiji adopted the name ,williamsonia pecten ,carr4#abbg for the specimens originally referred to ,w4 ,leckenbyi as well as for microsporophylls that he believed to belong to the same plant as the ovulate strobili3 but in a later paper#abbh he restricts the name ,williamsonia pecten to the male strobili1 reserving ,w4 ,leckenbyi for the ovulate forms1 as there is no proof that both were borne on the same plant4 ,from the evidence at present available it is reasonable to regard ,w4 ,leckenbyi as a unisexual flower4 ,in all probability the fronds known as ,ptilophyllum pecten are the foliage of the parent-plant of ,w4 ,leckenbyi1 though in the absence of proof it is advisable to retain both names4 ,illustration3 ,fig4 #eed4 ,williamsonia ,leckenbyi4 ,micropyle and interseminal scale4 7,after ,nathorst47 ,williamsonia whitbiensis ,nathorst4 ,under this name ,nathorst#abbi described some interesting specimens of microsporophylls formerly attributed by him to ,williamsonia pecten1 but the discovery of additional material led him to distinguish the ,whitby 7,lower ,estuarine7 fossils as ,w4 whitbiensis1 retaining the name ,w4 pecten for the type originally figured by ,leckenby#abcj from the ,middle ,estuarine series at ,cloughton ,wyke on the ,yorkshire coast4 ,in the type-specimen1 #h-aj cm4 in diameter1 there are #ae linear segments coalescent basally into a thick cup differing from that of ,w4 spectabilis in the absence of a stalk 7figs4 #eee1 #eef74 ,a more important distinctive feature is the production of synangia on the simple sporophylls 7figs4 #eef1 ,b2 #efe1 ,b7 and not on special fertile segments as in ,w4 spectabilis 7fig4 #eeb74 ,the inner face of each sporophyll1 as seen in impressions1 shows two regular rows of small depressions1 one on each side of the median line2 these become gradually smaller towards the base of the cup-like disc 7figs4 #eee1 #eef74 ,on the actual carbonised surface of the inner face of the cup small and transversely elongated projections take the place of the depressions and these show the same decrease in size when traced from the free segments to the cupular organ4 ,nathorst obtained microspores only from the larger projections and none from the smaller1 a circumstance which may indicate that only the upper and larger synangia were fully developed#abca4 ,illustration3 ,fig4 #eee4 ,williamsonia whitbiensis4 7,after ,nathorst2 nat4 size47 ,illustration3 ,fig4 #eef4 ,williamsonia whitbiensis4 ,a1 male flower4 ,b1 sporophyll with synangia4 7,after ,nathorst47 ,this species is especially interesting as throwing light on the nature of one of the specimens 7from the ,whitby ,museum7 figured by ,williamson as a #8carpellary disc#abcb'3 the #8seeds' of ,williamson are no doubt1 as ,nathorst believes1 synangia1 while the smaller pairs of markings figured by ,williamson represent rudimentary synangia and not #8abortive ovules4' ,though the specific identity of ,williamson's specimen and ,williamsonia whitbiensis is not certain1 the latter is undoubtedly a closely allied form of a microsporophyll-verticil4 ,a specimen figured in #aijj as a flower of ,williamsonia pecten#abcc1 designated by ,nathorst ,williamsonia sp41 is a very similar if not an identical type2 it consists of a fairly deep basal cup the surface of which is characterised by the presence of several regular ridges between which are pairs of small depressions containing carbonaceous matter4 ,in the light of ,nathorst's researches it is clear that this is an incomplete example of a whorl of microsporophylls4 ,the base of the disc is incomplete1 but it is certain from the small size of the basal hole with torn edges that the cup could not have been attached to the base of a receptacle as are the microsporophylls in ,wieland's bisporangiate flowers of ,cycadeoidea4 ,the specimens referred by ,nathorst to ,williamsonia pecten#abcd 7,leck4 ex parte7 are similar to those described as ,w4 whitbiensis1 but differ in the texture of the cup and in the degree of cuticularisation of the synangial walls4 ,the synangia of ,w4 pecten are of the usual reniform type and multicellular as in ,w4 spectabilis4 ,williamsonia setosa ,nathorst4 ,the distinguishing features of this species#abce1 founded on material collected by ,dr ,halle from ,lower ,estuarine beds at ,whitby1 are 7i7 the greater number of linear sporophylls which bear numerous bristles or stout hairs1 7ii7 the loose coherence of the contracted proximal portion of the linear segments1 and 7iii7 a narrower basal disc in place of the deeper cup of other species4 ,one of the specimens referred to this species1 formerly regarded by ,nathorst as an infundibuliform organ of an ovulate strobilus of ,w4 gigas#abcf1 bears a striking resemblance to an ,indian fossil described by ,feistmantel from ,india#abcg4 ,indian species of ,williamsonia 7,flowers74 ,several specimens of ,williamsonia have been described from the ,rajmahal and other ,jurassic series in ,india1 some of which exhibit a close agreement with ,williamsonia gigas4 ,it is1 however1 noteworthy that no fronds of the ,zamites gigas type have been discovered in ,indian beds2 on the other hand the association of fronds of the same type as ,ptilophyllum pecten with ,williamsonian strobili is significant1 as also the occurrence of stems apparently identical in surface-features with ,english and ,mexican species4 ,williamsonia sp4 ,oldham and ,morris#abch figured a specimen from the ,rajmahal ,hills consisting of a circular disc enclosed by a zone of #8closely packed tubes1' the basal portion of an ovulate ,williamsonia strobilus1 which they regarded as a pressed mass of young leaves #8probably related to ,palaeozamia' ,ptilophyllum4 ,the figured specimen shows that the radially disposed #8tubes' surrounding the circular area are interseminal scales some of which are seen at the periphery in surface-view as small polygonal areas as in ,english specimens4 ,feistmantel#abci refigured this specimen and referred it to ,williamsonia gigas though on insufficient grounds4 ,to the same species ,feistmantel#abdj assigns two other specimens from the ,rajmahal series1 one of which consists of several narrow linear bracts partially enclosing a strobilus with a portion of the annular zone at the base in which the seminiferous scales are shown in longitudinal-view and a few in apical-view4 ,williamsonia sp4 cf4 ,williamsonia setosa ,nathorst4 ,illustration3 ,fig4 #eeg4 ,williamsonia sp4 ,a1 whorl of microsporophylls2 s1 synangia 7874 ,c1 side-view of the basal portion of ,a4 ,b1 part of a microsporophyll enlarged4 7,indian ,geological ,survey2 ,a1 nat4 size47 ,a third example from the same locality 7fig4 #eeg7 is described by ,feistmantel#abda as part of one of ,williamson's #8carpellary discs#abdb1' a comparison that is fully justified4 ,the accompanying drawing has been carefully made from the actual specimen3 portions of #aj very hairy bracts radiate in a horizontal plane from a continuous lamina with a wrinkled and ridged surface bent sharply back at right-angles to the bracts and forming a double curve as seen in the sectional view 7fig4 #eeg1 ,c74 ,the form assumed by the vertical part of the disc is1 ,i believe1 the result of compression4 ,wieland#abdc regards this fossil as a whorl of microsporophylls originally attached to the lower portion of the receptacle of a bisexual flower4 ,close to the edge of one of the bracts is an imperfectly preserved structure 7fig4 #eeg1 ,b1 s7 which may represent two alternately arranged rows of synangia belonging to one of the hairy bracts2 but we have no evidence as to the position of the microsporophylls on the flower-axis4 ,the central space enclosed by the crushed concrescent portion of the disc is large enough to have embraced a receptacle but1 on the other hand1 the portion preserved may have broken off from a proximal cup like that of ,w4 spectabilis#abdd1 which1 as ,nathorst's specimens show1 is sometimes broken across near the upper edge of the basal funnel4 ,this specimen is spoken of by ,feistmantel as ,williamsonia gigas4 ,it is impossible to say whether these ,rajmahal specimens belong to one species1 and they are therefore provisionally designated ,williamsonia sp4 and ,williamsonia sp4 cf4 ,w4 setosa4 ,williamsonia microps ,feistmantel4 ,this species is based on a compressed ovate strobilus surrounded by linear bracts and a portion of the cylindrical axis#abde4 ,it is possible that this smaller1 bud-like1 specimen may be a younger example of the species referred by ,feistmantel to ,williamsonia gigas4 ,williamsonia ,blandfordi ,feistmantel4 ,founded on a small strobilus enclosed by linear bracts1 from the ,jurassic rocks of ,cutch#abdf1 very similar to ,williamsonia pecten2 as seen in fig4 #eeh1 drawn from the original specimen1 the flower is associated with a ,ptilophyllum frond indistinguishable from some examples of ,ptilophyllum pecten4 ,williamsonia indica1 sp4 nov4 ,this name is proposed for some imperfect specimens described by ,feistmantel from the ,godaveri district and named by him ,williamsonia sp4 cf4 ,williamsonia gigas#abdg4 ,they differ from ,williamsonia gigas in the larger size of the bracts which reach a length of #ac cm4 and may be compared with those of a large specimen recorded from ,mexico as ,williamsonia ,cuauhtemoc#abdh4 ,illustration3 ,fig4 #eeh4 ,williamsonia ,blandfordi and ,ptilophyllum frond4 7,geological ,survey of ,india2 nat4 size47 ,it is almost certain that some at least of the ,indian flowers were borne on stems with the foliage known as ,ptilophyllum acutifolium1 an inference based not only on the almost constant association of flowers and fronds but also on the juxtaposition of both kinds of organs with stems precisely similar to those described from ,england and ,mexico4 ,though none of the specimens are sufficiently well preserved to afford much information as to structural features1 ,miss ,bancroft#abdi has shown that the bracts of one of the examples assigned by ,feistmantel to ,w4 gigas are similar anatomically to those of ,williamsonia scotica and are clothed with simple hairs4 ,the important point is the very close correspondence between the ,indian and ,english types of ,williamsonia1 as regards flowers1 fronds1 and stems4 ,british ,specimens4 ,williamsonia ,carruthersi ,seward4 ,illustration3 ,fig4 #eei4 ,williamsonia ,carruthersi4 ,a1 unexpanded flower4 ,a1 the reticulate lamellae projecting from the face of a bract4 ,b1 the basal portion of a larger and expanded flower showing the impressions of the interseminal scales and the base of the receptacle4 7,british ,museum1 ,a1 ,v4 #cagg2 ,b1 ,v4 #cbja47 ,this species was founded on several specimens from ,wealden beds on the ,sussex coast none of which afford information as to anatomical structure#abej4 ,it is not improbable that more than one species is represented4 ,the ovulate cone1 #f cm4 long1 is surrounded by several linear bracts 7fig4 #eei1 ,a7 and in shape resembles ,bennettites ,morierei ,lign42 the bracts are broken across near the base1 as is frequently the case in ,williamsonia gigas1 exposing an annular zone formed by persistent interseminal scales4 ,from the inner face of some of the bracts project slender radiating plates 7fig4 #eei1 ,a7 which no doubt mark the boundary of the superficial and relatively large interseminal scales1 like those forming the so-called pericarp in ,bennettites ,gibsonianus4 ,the receptacle appears to have been conical1 a feature recalling ,bennettites rather than ,williamsonia4 ,the saucer-like impression shown in fig4 #eei1 ,b1 is practically identical with the corresponding portion of ,williamsonia ,leckenbyi3 the centre is occupied by a raised area1 the basal part of the receptacle1 on which a series of peripheral prominences represents the vascular strands2 the sides of the saucer show very clearly the reticulum formed by the distal ends of interseminal scales4 ,one reason for assigning this species to ,williamsonia rather than to ,bennettites 7or ,cycadeoidea7 is the occurrence in the same bed of a peduncle #ab cm4 long and #c cm4 broad which probably belonged to the parent-plant of the cone4 ,the surface of the peduncle shows spirally disposed scars of bracts crowded at the distal end and more widely separated in the lower portion4 ,williamsonia ,bucklandi 7,unger74 ,in #ahcg ,buckland#abea gave an account of a #8unique and beautiful fossil fruit' from ,inferior ,oolite beds at ,charmouth in ,dorsetshire and stated that the type-specimen was in the ,oxford ,museum4 ,professor ,sollas kindly searched for the specimen some years ago but without success4 ,buckland considered that the fruit was related to the ,pandanaceae and described it as follows3 #8,the size of this fruit is that of a large orange1 its surface is occupied by a stellated covering or epicarpium1 composed of hexagonal tubercles1 forming the summits of cells1 which occupy the entire circumference of the fruit4 ,within each cell is contained a single seed1 resembling a small grain of rice more or less compressed1 and usually hexagonal4 ,when the epicarpium is removed1 the points of the seeds are seen1 thickly studded over the surface of the fruit4 ,the bases of the cells are separated from the receptacle by a congeries of foot-stalks formed of a dense mass of fibres1 resembling the fibres beneath the base of the seeds of the modern ,pandanus4' ,at the suggestion of ,robert ,brown he called the #8fruit' ,podocarya1 the specific name ,bucklandi being afterwards given by ,unger#abeb4 ,brongniart#abec called attention to the resemblance of ,buckland's specimen to ,williamsonia1 and that name has been adopted by ,saporta#abed1 ,nathorst1 and other authors#abee4 ,sowerby's drawings illustrating the original description1 one of which is reproduced in fig4 #efj1 show that this unusually fine specimen is an ovulate ,bennettitean strobilus very similar in its thick conical receptacle to some of ,wieland's species of ,cycadeoidea1 e4g4 ,c4 dacotensis 7fig4 #ebh73 the armour of scales and megasporophylls agrees exactly with that of some species of ,williamsonia from ,yorkshire and with the flowers of ,cycadeoidea4 ,though included in the genus ,williamsonia it would not be out of place in ,cycadeoidea4 ,illustration3 ,fig4 #efj4 ,williamsonia ,bucklandi4 7,after ,buckland2 nat4 size47 ,williamsonia scotica ,seward4 ,the type-specimen was found by ,hugh ,miller near ,cromarty 7,n4,e4 ,scotland7 and figured as a cone of peculiar form#abef2 it was obtained from a limestone nodule probably derived from ,upper ,jurassic rocks4 ,the fossil is #aa cm4 long and has a maximum breadth of #f cm4 7fig4 #efa73 numerous linear bracts cover the surface and in the lower portion many of them are broken4 ,a noteworthy feature is the absence of any clean-cut base1 a fact pointing to fracture rather than a natural abscission of the fertile axis4 ,the following description may serve to give a general idea of the salient characters4 ,flowering shoot ovoid1 covered with linear bracts some of which are prolonged above the conical apex as slender tapered organs and two of them bear a few short lateral appendages 7fig4 #efa1 l71 probably reduced leaflets1 near their distal ends4 ,the cylindrical axis1 completely hidden by bracts1 #ae cm4 in its widest part1 bears in the lower or sterile region bracts and long hairs and in the upper part interseminal scales and immature megasporophylls which together form a narrow band 7fig4 #efb1 ,s7 #b mm4 broad extending over the incompletely preserved and conical apex1 as in some of the ,american examples of ,cycadeoidea4 ,the strobilus was probably borne at the apex of a lateral branch given off from a stem covered with persistent petiole-bases3 there is no evidence that this was the case1 but the appearance of the ovoid cone suggests comparison with those of ,williamsonia gigas which were terminal on fairly long branches and not partially hidden among the bases of fronds as in ,cycadeoidea4 ,it is1 however1 possible that the cone of ,williamsonia scotica is a lateral structure3 this suggestion is based on the occurrence of a small branch or bud1 which may be the apex of the whole fertile shoot1 given off from the cone-axis but only revealed in transverse sections4 ,the interseminal scales1 #b mm4 long and #jbc mm4 broad at the truncate distal end 7fig4 #efc71 are polygonal in section and arranged as rosettes of #e-f around each megasporophyll 7fig4 #efd1 a section tangential to the peripheral layer of scales and sporophylls74 ,the megasporophylls1 equal in length to the scales1 consist of a cylindrical axis bearing a terminal megasporangium1 an undifferentiated nucellus1 enclosed in a single integument prolonged as a micropylar tube above the conical end of the nucellus 7fig4 #efc1 ,b1 ,c1 a74 ,fig4 #efb represents a transverse section through the cone showing the cylindrical axis with its compact covering layer 7fig4 #efc1 ,a1 s7 of sterile and fertile appendages1 and beyond this sections of the enveloping bracts embedded in a dense felt of long hairs4 ,the tissue of the axis1 though very imperfectly preserved1 shows occasional groups of secretory sacs and a few patches of scalariform tracheids3 there is evidence of the occurrence of peripheral conducting tissue in the lower portion of the axis such as occurs in the peduncles of ,american species of ,cycadeoidea described by ,wieland4 ,the bracts nearer the axis are more shrivelled than those farther away1 the result of the feebler development of hypodermal stereome in the more internal bracts4 ,sunken stomata occur on the lower surface of some of the bracts3 several collateral bundles are present in each and large secretory ducts are abundant4 ,the numerous hairs on the bracts and the sterile region of the cone are outgrowths of epidermal cells2 most of them consist of a short basal cell and a very long thick-walled tubular hair reaching a length of several centimetres4 ,in some cases the basal cell bears a group of short cells each of which is the starting-point of a long hair3 this is worthy of notice from the point of view of comparison with the ramenta of other ,bennettitalean flowers4 ,the short proximal cell of a hair is surrounded by a cuticular ring like a rounded base-moulding where it rests on the epidermis3 this has been aptly compared to the dark rings that form a striking feature of the cuticular membrane of ,ptilophyllum leaflets#abeg4 ,illustration3 ,fig4 #efa4 ,williamsonia scotica4 ,strobilus in surface-view2 l1 bract with short lateral appendages4 7,royal ,scottish ,museum1 ,edinburgh2 nat4 size47 ,illustration3 ,fig4 #efb4 ,williamsonia scotica4 ,transverse section2 ,s1 scales and megasporophylls2 a1 bract showing detached superficial tissue on the inner side4 7ca4 #b47 ,illustration3 ,fig4 #efc4 ,williamsonia scotica4 ,megasporophylls and interseminal scales in longitudinal section4 ,a1 part of the axis showing the attachment1 s1 of a scale and megasporophyll4 ,b1 apex of micropylar tube showing funnel-shaped cavity and papillose epidermal cells on the integument and on the adjacent scale2 a1 apex of nucellus4 ,c1 upper part of a scale and megasporophyll2 a1 apex of nucellus4 7,a1 ca4 #bj2 ,b1 ,c1 #ajj47 ,illustration3 ,fig4 #efd4 ,williamsonia scotica4 ,transverse section near the distal end of a micropylar tube and the surrounding polygonal interseminal scales4 7ca4 #ajj47 ,in the examination of the type-specimen the first section cut was transverse to the axis 7fig4 #efb71 and this happened to traverse the lowest part of the fertile region of the receptacle1 as was shown by the fact that in the next lower section the axis bore only bracts and hairs4 ,it is clear that the sterile portion of the receptacle passed abruptly upwards into the fertile region1 and it is extremely unlikely that any microsporophylls were borne at the base of that portion of the cone-axis which produced the scales and megasporophylls4 ,the cone was1 in all probability1 unisexual4 ,on the analogy of the cones shown in figs4 #eac1 #ead1 one would expect to find between the sterile and fertile regions either a verticil of microsporophylls or the remains of an annular disc from which the effete sporophylls had been detached4 ,there is no trace of any such disc1 and the fact of the immaturity of the megasporophylls renders it unlikely that were the cone bisexual the microsporophylls would have been detached4 ,as previous records show1 there is nothing improbable in the occurrence of a unisexual ,bennettitean flower4 ,these remarks are made in view of an opinion expressed by ,dr ,wieland that the bracts with lateral appendages 7fig4 #efa1 l71 to which allusion has been made1 are microsporophylls and that if the cone had been sliced longitudinally the presence of a microsporophyll-disc would have been discovered4 ,the latter possibility has already been considered1 and as regards the former there is nothing in the structure of the small lateral appendages of the longest bracts to indicate that they were connected with spore-production4 ,it is not unlikely that the bracts with small outgrowths 7fig4 #efa1 l7 correspond to the more leaf-like bracts of ,wielandiella and ,williamsoniella4 ,the two sets of organs spoken of as interseminal scales and megasporophylls are probably homologous1 foliar1 structures2 in the one case leaves transformed into cylindrical organs bearing terminal integumented and undifferentiated megasporangia and1 in the other1 sterile or sterilised sporophylls4 ,the polygonal truncate distal end of an interseminal scale is flat or slightly concave and covered by a thick epidermis1 and on the sides of the scale many of the surface-cells are strongly papillose 7figs4 #efc1 #efd74 ,the rest of the interseminal scale consists mainly of elongated cells1 which in the lower portion of the axis of the scale assume a tubular form1 presumably immature conducting elements3 in one scale only was any tracheal tissue found and that was represented by #b-c scalariform tracheids4 ,the scales appear to arise from the axis like the bracts as superficial outgrowths1 and probably in a later stage of development the centre of each scale would be occupied by a vascular strand4 ,the megasporophylls bear a close resemblance to the scales1 but in transverse section they appear as smaller and circular organs each the centre of a group of polygonal interseminal scales precisely as in other ,bennettitean flowers 7fig4 #efd2 cf4 fig4 #eae74 ,the proximal part of a megasporophyll consists of a column of parenchyma 7fig4 #efc1 ,a1 s7 extending through half of the length2 from this column is detached a narrow cylinder of small crushed cells which most likely represents the remains of tissue that originally occupied the space surrounding the axial column4 ,at a higher level the axial column becomes broader and its short cells more elongated and slightly divergent towards the sloping sides of the conical nucellus4 ,the loose cylinder of tissue is attached to the nucellar cone and prolonged beyond its apex as a broad integument enclosing a very small micropyle 7fig4 #efc1 ,c74 ,the apex of the integument has the form of a shallow funnel3 its epidermal cells are papillose 7fig4 #efc1 ,b1 ,c7 and the presence of short transversely elongated cells is a characteristic feature of the tissue lining the micropylar canal4 ,the bracts agree generally with those of ,cycadeoidea ,gibsoniana1 ,cycadeoidea ,morierei1 and the ,american species4 ,the ground tissue is composed of sclerenchyma comparable with the scalariform elements in the bracts of ,cycadeoidea ,gibsoniana 7cf4 fig4 #ebj74 ,it is in the possession of long hairs like those on the leaves of ,dioon and other recent ,cycads that ,williamsonia scotica differs from previously described flowers in all of which the fern-like ramental scales are a conspicuous feature4 ,it is interesting to find that similar hairs are substituted for scales in some ,indian stems described by ,miss ,bancroft#abeh4 ,lignier#abei mentions the occurrence of long unicellular hairs on ,cycadeoidea micromyela 7p4 #dae71 a ,jurassic ,french species1 but the ramenta are in part multicellular lamellae and the presence of transitional forms suggests a possible derivation of hairs from scales both in fossil species and in recent ,cycads4 ,the megasporophylls and interseminal scales are much shorter than in ,cycadeoidea ,gibsoniana and other species in which the axis of the cone forms a depressed receptacle 7cf4 fig4 #eba1 ,a1 ,c71 but they correspond closely with those of several ,american species4 ,in ,cycadeoidea ,gibsoniana and ,c4 ,morierei the distal ends of the interseminal scales are much broader and their diameter greatly exceeds that of the micropylar tubes1 #bh mm4 as compared with #jbe mm41 whereas in ,williamsonia scotica the scales are #jbc mm4 broad and the micropylar tubes #jae mm4 ,the mummified micropylar tubes of ,w4 pecten bear a striking resemblance in form and in the papillose epidermal cells to those of the ,scotch species4 ,there are two additional points suggested by the structure of the fertile region1 namely the possibility that the megasporophylls are arrested rather than immature organs and1 secondly1 the method of pollination4 ,in regard to the first there would seem to be no adequate reason for doubting the correctness of the view that the sporophylls are potentially perfect ovules which were petrified at a comparatively early stage in development4 ,the dense woolly covering investing the surface of the scales and megasporophylls recalls an inflorescence of ,aesculus hippocastanum in its winter-fur and hardly suggests a collection of ovules accessible to microspores4 ,in all probability at a later stage the protecting bracts with their felt of hairs would bend outwards leaving exposed the receptive micropyles4 ,microsporophylls4 ,in view of the association of microsporophylls and ovulate strobili in the flowers of ,cycadeoidea described by ,wieland1 most of which are bisexual1 it is reasonable to expect a similar association in the flowers of ,williamsonia which agree closely in the essential features of both micro- and mega-sporophylls with those of ,cycadeoidea4 ,it is1 therefore1 surprising that in no single case have the microsporophylls attributed to ,williamsonia been found in actual connexion with a receptacle bearing interseminal scales and megasporophylls4 ,the same statement holds good with regard to the ,williamsonias discovered in ,mexico4 ,nathorst believes that the microsporophylls on which he has founded several species are unisexual flowers with the possible exception of ,w4 pyramidalis#abfj4 ,this species1 found by ,dr ,halle at ,cloughton ,wyke1 is represented by a small ovulate strobilus characterised by a conical receptacle with a blunt mucronate apex3 with it is associated a microsporophyll bearing synangia4 ,the orientation of the two specimens is such as to suggest an original connexion4 ,as ,nathorst says1 there is1 however1 no proof that the two belong to one flower4 ,wieland#abfa1 though believing that the existence of bisporangiate ,williamsonia flowers is #8reasonably certain1' agrees with ,nathorst's conclusion as to the unisexual character of ,w4 spectabilis and ,w4 pecten4 ,on the other hand1 he regards the microsporophyll-verticil which was first described by ,williamson as a carpellary disc1 then named by ,nathorst#abfb ,w4 bituberculata and afterwards identified as a microsporophyll-disc closely allied to ,w4 whitbiensis1 as the staminate part of ,w4 gigas4 ,this view is1 in my opinion1 impossible to reconcile with the nature of the specimen4 ,if1 as ,wieland suggests1 it is the staminal collar split off from the base of a large ovulate cone like that of ,williamsonia gigas1 one would expect to find a central space in the middle of the cupular base large enough to embrace the receptacle4 ,neither in this specimen nor in several other forms of microsporophyll-verticils is there such a central space4 ,it is clear that the discs described as ,w4 spectabilis1 ,w4 whitbiensis1 and other species were not borne as concrescent collars on a stout axis as are the corresponding organs in ,cycadeoidea4 ,the ,indian specimen reproduced in fig4 #eeg and the very closely allied type ,w4 setosa are incomplete at the centre and may possibly have been borne at the base of an ovulate bisporangiate strobilus1 but there is no definite evidence that this was the case4 ,moreover1 in ,w4 spectabilis the lower part of the cup 7fig4 #eea7 easily splits away from the rest of the staminate disc1 and this may explain the central space in the specimen shown in fig4 #edi1 ,a4 ,if ,w4 spectabilis1 to take one example1 is a complete flower there are certain difficulties which are not easily explained3 as ,nathorst has shown1 in this type there is a short stalk1 but in ,w4 whitbiensis the base of the funnel has no stalk and there is no interruption of the stout lamina at the centre or any indication of a scar4 ,nathorst compares the funnel-like region of ,w4 whitbiensis to a kind of cupule which became detached after flowering#abfc4 ,but a cupule is supported on an axis and1 though no scar is apparent on some of the more complete specimens1 it is obvious that the verticil must have been supplied with vascular tissue from some axial organ4 ,this brings us to the consideration of a morphological point which cannot be definitely answered4 ,nathorst has previously raised the question--is it possible that the microsporophylls were attached to the upper part of an ovulate strobilus2 were the flowers bisexual and epigynous8 ,he believes the answer to be in the negative4 ,reference has already been made to the probable occurrence at the apex of the receptacle of ,williamsonia gigas of a funnel-like organ of the type described by ,williamson as #8carpellary disc#abfd1' a term under which ,nathorst#abfe believes that ,williamson included two different things1--staminate discs borne on separate1 unisexual1 flowers1 and sterile organs called by ,lignier#abff the infundibuliform apparatus4 ,the latter1 it is believed1 were attached to the apex of an ovulate strobilus as shown in fig4 #edh1 comparable in position with the leaves at the summit of an inflorescence of ,ananas4 ,a comparison of the fossils regarded as infundibuliform appendages with some of the microsporophyll-verticils shows that they are identical in form1 the only difference being that on the former there are no synangia4 ,this fact can hardly be regarded as negative evidence fatal to the morphological identity of these sterile and fertile organs4 ,the available evidence1 though far from complete1 is favourable to the view that in some ,williamsonia flowers1 e4g4 ,w4 gigas1 the microsporophylls were produced at the apex of the axis in the position shown in fig4 #edh4 ,to cite a rough analogy1--in ,cycadeoidea the flower was hypogynous as in ,erica2 in ,williamsonia epigynous as in ,vaccinium4 ,this view does not exclude the possibility of the existence of unisexual flowers in some species1 but the evidence in favour of a separation of the sexes is by no means decisive4 ,another difficulty is the absence of protective bracts in the case of the microsporophylls1 a striking contrast to the bract-enclosed ovulate strobili of ,williamsonia or to the bract-covered flowers of ,cycadeoidea4 ,were the microsporophylls borne on a separate axis general considerations would lead us to expect the association of bracts with the essential organs4 ,the fact that no such association has been recorded is a fact favourable to the view that the flowers were bisporangiate4 ,illustration3 ,fig4 #efe4 ,a1 ,williamsonia spectabilis1 microsporophyll2 ,b1 ,w4 whitbiensis1 section of sporophyll2 ,c1 ,w4 mexicana4 7,a1 ,b1 after ,nathorst2 ,c1 after ,wieland47 ,the student is warned that the opinion expressed with regard to the position of the microsporophylls is contrary to that which is held by several palaeobotanists#abfg4 ,williamsonia mexicana ,wieland4 ,this species is one of the numerous types discovered by ,wieland in ,mexico#abfh4 ,it is distinguished by the deep campanulate concrescent portion of the whorl of microsporophylls and by the ten short free lobes which bear two rows of lateral synangia 7fig4 #efe1 ,c74 ,among the ,british forms ,williamsonia whitbiensis would appear to be the most closely allied type4 ,w4 mexicana occurs in association with ,otozamites fronds1 as is the case with an ,italian specimen figured by ,zigno#abfi1 but in the ,mexican species there is no conclusive evidence of organic connexion4 ,other species of ,williamsonia4 ,williamsonia ,haydeni ,seward4 ,a ,jurassic species from ,afghanistan#abgj founded on a single specimen of a flattened broadly-oval flower similar to ,w4 gigas but smaller and enclosed by narrow linear bracts4 ,an interesting feature is the occurrence of a funnel-shaped depression at the apex showing radiating lines on its surface as in the ,williamsonia represented in fig4 #edf1 ,a4 ,in all probability these lines denote the persistence of a collar of interseminal scales on the upper part of the elongated conical receptacle4 ,an examination of the carbonaceous material revealed the presence of some short rods agreeing in size and shape with the interseminal scales of other species4 ,williamsonia ,otozamitis 7,zigno74 ,zigno#abga instituted the generic name ,blastolepis for some specimens from the ,jurassic rocks of north ,italy which he referred to three species1 ,b4 falcata1 ,b4 acuminata1 and ,b4 ,otozamitis4 ,these are true ,williamsonias closely allied to ,w4 gigas4 ,an examination of the type-specimen of ,b4 ,otozamitis in the ,padua collection led me to the conclusion that ,zigno was correct in representing the ovulate strobilus1 which shows an annular area like that in specimens of ,w4 gigas1 as being in organic connexion with an ,otozamites frond4 ,wieland has recently discovered species of ,williamsonia in ,mexico that he correlates with ,otozamites leaves4 ,williamsonia sp4 ,seward4 ,though by no means satisfactory as a trustworthy record of the genus1 the specimens so designated from the ,kimmeridgian of ,scotland#abgb are probably imperfect examples of the genus4 ,williamsonia oregonensis ,fontaine4 ,the type-specimen from ,jurassic rocks in ,oregon#abgc consists of a stout axis bearing several contiguous linear bracts forming a more or less spherical cluster #e cm4 broad4 ,the form suggests a ,williamsonia1 but the evidence is hardly decisive4 ,williamsonia ,forchammeri ,nathorst4 ,a ,bornholm species#abgd from ,lower ,jurassic strata represented by an annular zone surrounding a central area1 probably a portion of an ovulate strobilus4 ,williamsonia minima ,saporta4 ,this ,upper ,jurassic species from ,portugal#abge consists of a number of small bracts or leaves attached to a central axis and is of no value as evidence of the occurrence of ,williamsonia4 ,williamsonia problematica 7,newberry74 ,this species was first described from the ,amboy clays as ,palaeanthus 7,williamsonia7 problematica#abgf and compared to a ,composite inflorescence with long ray-florets4 ,more recently ,hollick#abgg has referred to this species specimens from the ,cretaceous of ,long ,island and ,martha's ,vineyard1 but none of them afford conclusive evidence of ,williamsonian affinity4 ,some of the examples1 as suggested by ,hollick1 agree fairly closely with ,williamsonia cretacea ,heer4 ,williamsonia ,smockii ,newberry4 ,the curious urn-like bodies from the ,amboy clays#abgh on which this species is based are not unlike the capsules of a ,papaver but bear no real resemblance to a ,williamsonia4 ,williamsonia ,riesii ,hollick4 ,a species from the ,cretaceous rocks of ,martha's ,vineyard#abgi referred to ,williamsonia on rather slender grounds and represented by imperfect material4 ,williamsonia 787 phoenicopsoides ,ward4 ,this fossil from the ,cretaceous of the ,black ,hills1 ,dakota#abhj1 is much too imperfect to be accepted as a record of ,williamsonia4 ,williamsonia elongata ,lesquereux4 ,this species1 founded on part of a conical receptacle with some appendages superficially resembling those of ,williamsonia#abha1 is too incomplete to be determined with any confidence4 ,the type-specimen is from ,cenomanian beds in ,kansas4 ,williamsonia virginiensis ,fontaine4 ,this is undoubtedly a true member of the genus2 it is characterised by narrow ovate bracts bearing conspicuous hairs surrounding the base of a receptacle which shows a portion of an annular zone of interseminal scales#abhb4 ,williamsonia 787 gallinacea ,ward4 ,this species from the ,potomac beds#abhc is of no value as a record of ,williamsonia4 ,williamsonia 787 ,bibbinsi ,ward4 ,the imperfectly preserved specimen from the ,potomac series so named by ,ward#abhd is probably part of an ,abietineous cone as stated by ,berry#abhe who includes ,ward's type with other specimens referred to ,abietites macrocarpus ,font4 ,williamsonia cretacea ,heer4 ,two specimens1 figured by ,heer#abhf from the ,lower ,cretaceous of ,greenland1 on which this species is founded1 consist of an axis covered with small scale-leaves and at the broad apex bearing numerous narrow linear bracts forming a more or less spherical cluster #ch cm4 in breadth4 ,the species resembles ,w4 problematica 7,newb474 ,williamsonia recentior ,dawson4 ,the specimens from the ,middle ,cretaceous of ,canada figured by ,dawson#abhg under this name are very imperfect and of no botanical value4 ,illustration3 ,fig4 #eff4 ,wielandiella angustifolia4 7,after ,nathorst47 ,,wielandiella4 ,nathorst4 ,the specimens on which this genus is founded were originally described by ,nathorst from ,hr in ,scania as ,williamsonia angustifolia#abhh3 in a second paper#abhi a restoration of the plant was published 7fig4 #eff74 ,the examination of additional specimens from the ,rhaetic of ,bjuf and of cuticular preparations led to the establishment of a new genus ,wielandia#abij for which ,wielandiella#abia was afterwards substituted1 ,wielandia having been previously employed for an existing plant4 ,wielandiella agrees in the general morphology of its bisporangiate flowers with ,cycadeoidea1 but differs widely from nearly all other members of the ,bennettitales in the repeatedly forked slender stem which is in marked contrast to the vegetative axis of any recent ,cycad4 ,among recent ,cycads with terminal strobili an indication of a primitive dichasium is afforded by the occurrence of an aborted bud in a stem of ,dioon edule described by ,south and ,compton#abib2 but in the habit of the stem ,wielandiella is far removed from any recent ,cycadean type4 ,the microsporophylls are smaller and simpler than in ,williamsonia or ,cycadeoidea and the foliage-leaves are of the ,anomozamites type 7cf4 fig4 #fae74 ,illustration3 ,fig4 #efg4 ,wielandiella angustifolia4 ,branched stem and receptacle4 7,after ,nathorst47 ,wielandiella angustifolia ,nathorst4 ,in an account of this species in #aijb ,nathorst described two types of strobilus1 male and female1 but a re-investigation of the material led to a modification of the earlier conclusions4 ,the stem is slender1 rarely exceeding #ae cm4 in breadth1 repeatedly branched as a dichasial system with a fertile shoot in the forks formed by the equal and widely divergent branches4 ,nathorst's restoration1 as he points out1 may exaggerate the regularity of the branching1 but an examination of the original specimens in the ,stockholm ,museum convinced me that the habit represented in fig4 #eff is substantially correct4 ,the method of branching is similar to that in the inflorescences of ,gnetalean plants and recalls some ,gleichenia fronds4 ,the surface of the thicker pieces of stem shows fine longitudinal striae1 while transverse striations like those on the axis of a ,heterangium frond characterise the more slender specimens4 ,closely set polygonal leaf-scars cover the stem for a short distance below each bifurcation and the surface of the short and relatively stout peduncles of the strobili 7fig4 #efg74 ,though for the most part confined to the region of false dichotomy1 leaf-scars occasionally occur on other parts of the stem4 ,small fronds1 #g-h cm4 long1 agreeing closely with ,anomozamites minor ,brongn41 occur in the same beds at ,bjuf1 and the striking resemblance between their long linear and winged petioles and the transversely striated bracts enclosing the strobili of ,wielandiella amply justifies ,nathorst's conclusion that ,wielandiella bore fronds of the ,anomozamites form#abic4 ,small scars marking the position of bracts occur immediately below each strobilus and occasionally form narrow zones between the larger foliage leaf-scars4 ,the strobili are met with in two forms representing two states of preservation and1 probably1 different ages4 ,in one form the strobilus consists of a small pyriform axis separated from the peduncle by an annular swelling characterised by parallel striations 7fig4 #efg71 the so-called palisade-ring4 ,from this ring ,nathorst obtained many microspores scattered and in groups on the surface of short sporophylls1 #be-c mm4 in length4 ,it is these sporophylls which form the parallel striations2 they occur as a circle of rather broad linear organs with irregularly toothed distal ends and an epidermis of papillose cells4 ,the oval microspores1 #cb-db long1 vary in size and1 as ,nathorst says1 this may indicate immaturity4 ,the precise mode of occurrence of the spores has not been ascertained1 but they were probably produced in sporangia on the surface of the small microsporophylls4 ,these strobili have in all probability lost the female organs which were borne on the pyriform axis1 and the inference is that the strobili were protogynous4 ,thomas#abid compares the ring at the base of the flower-axis from which spores were obtained by ,nathorst to the whorl of microsporophylls of ,williamsoniella1 but in ,wielandiella the sporophylls are greatly reduced and possibly functionless4 ,wielandiella may be intermediate between the bisexual ,williamsoniella and the unisexual ,williamsonia scotica4 ,in the second form of strobilus the pyriform axis is hidden and the specimens consist of a central ovate body1 approximately #c cm4 long1 surrounded by several linear bracts 7fig4 #efh1 ,a74 ,the carbonised surface of the central region revealed on chemical treatment a fairly regular pattern formed by the contiguous polygonal ends of interseminal scales arranged round smaller cylindrical micropylar tubes which project beyond the level of the scales 7fig4 #efh1 ,b74 ,this arrangement agrees closely with that of the corresponding organs in ,williamsonia and ,cycadeoidea 7cf4 figs4 #eae1 #efd74 ,in ,wielandiella the micropylar tubes are of uniform diameter and the cells of the epidermis have smooth walls in contrast to the micropylar tubes of ,williamsonia 7fig4 #efc74 ,the strobilus in this state1 before the scales and ovules have become detached from the axis1 may be described as a small ,williamsonia1 but the habit of the stem is in itself a sufficient reason for the use of a distinctive generic name#abie4 ,illustration3 ,fig4 #efh4 ,wielandiella angustifolia4 ,a1 conical receptacle with bracts4 ,b1 surface-view of scales and micropylar tubes4 7,after ,nathorst2 ,a1 nat4 size47 ,a second species1 ,wielandiella punctata1 described by ,nathorst#abif from ,scania is founded on pieces of forked stems associated with fragments of a palisade-ring formed of contiguous segments 7microsporophylls7 with microspores #eh in length4 ,fronds of ,anomozamites minor occur in the same beds4 ,mr ,hamshaw ,thomas#abig described some specimens from the ,middle ,jurassic beds of ,marske in ,yorkshire which he suggested might be pieces of a ,wielandiella stem4 ,additional material was subsequently found and this enabled ,thomas to produce evidence in favour of connecting the branched vegetative axis with bisporangiate strobili and the fronds of ,taeniopteris vittata4 ,for the stems and flowers the new designation ,williamsoniella has been proposed4 ,further research will no doubt show that the ,wielandiella type of stem was not exceptional in ,rhaetic and ,jurassic floras4 ,nathorst#abih suggests the possibility that some specimens from the ,solenhofen ,slates described by ,thiselton-,dyer#abii as ,condylites squamatus may be allied to ,wielandiella4 ,the generic name ,condylites was suggested by the elbow-like branching of stems which bore imperfectly preserved and apparently terminal cones2 the surface of the branches is covered with the scars of leaves4 ,the resemblance to ,wielandiella is1 however1 slight and it would seem more probable that the ,solenhofen fossils are ,coniferous1 though1 as ,nathorst says1 the supposed scale-like #8leaves' may be scars of ,cycadean fronds4 ,wieland#acjj records the occurrence in ,mexico of stems similar to those of ,wielandiella associated with some ,otozamites fronds4 ,,williamsoniella4 ,thomas4 ,this genus was instituted for specimens discovered by ,mr ,hamshaw ,thomas#acja in the ,middle ,estuarine series of the ,middle ,jurassic plant-bed at ,gristhorpe on the ,yorkshire coast1 and the genus is recorded also from the ,cleveland district in the same county4 ,williamsoniella occurs in those parts of the ,gristhorpe bed where fronds of ,taeniopteris vittata are abundant4 ,williamsoniella coronata ,thomas4 ,the type-species is represented by fertile shoots consisting of a central axis bearing both megasporophylls and microsporophylls 7figs4 #efi1 #ega1 ,a74 ,below its crown-like sterile apex the pyriform peduncle is covered with small interseminal scales and ovules similar to those of ,williamsonia3 this portion is #f mm4 in diameter and #a cm4 long4 ,a whorl of separate cuneate microsporophylls forms a hypogynous ring below the basal interseminal scales3 each sporophyll is attached by a narrow base 7fig4 #egj7 and bears #e-f reniform synangia containing microspores4 ,the flower is thus bisexual3 it affords no conclusive evidence of the occurrence of any covering bracts like those of most ,bennettitalean flowers4 ,in young specimens the microsporophylls are closely packed round the axis 7fig4 #ega1 ,b74 ,the flower-stalks reach a length of #ce cm4 and are #c mm4 in diameter4 ,fig4 #ega1 ,c1 shows a receptacle from which the sporophylls have fallen3 the microsporophylls having been no doubt attached to the collar-like swelling at the base4 ,towards the apex the axis becomes broader and at s a few interseminal scales are left3 above these is the apical disc 7corona7 characterised by longitudinal ribs4 ,an apical disc is reproduced in fig4 #egb2 it has the form of a royal crown #a-b mm4 high with #ab-af vertical ridges separating flat surfaces formed by the pressure of microsporophyll apices in the unexpanded flower4 ,the corona is surmounted by a small conical elevation which represents the apex of the fertile axis4 ,an apical view of an unexpanded flower is shown in fig4 #ega1 ,b2 the tips of #ab sporophylls are closely pressed against the corona which probably consists in part at least of fused interseminal scales4 ,the microsporophylls were shed after the dehiscence of the synangia4 ,each sporophyll is flattened on the sides and thicker on the curved outer edge2 the synangia1 usually in two rows of three1 are borne on the sloping sides 7figs4 #efi1 #egj74 ,the surface of a microsporophyll is covered with small rounded projections which produce a characteristic appearance4 ,the form of a microsporophyll in section is shown in fig4 #egj3 the synangia are similar in shape to those of ,cycadeoidea and ,williamsonia 7cf4 figs4 #eca1 #edi1 etc47 but there are no external indications of septa like those seen in some other types4 ,on macerating some specimens it was found that the spores occur in about #bj groups4 ,the circular or elliptical spores are #jjb mm4 in diameter4 ,the walls of the epidermal cells of the microsporophylls are straight3 the stomata1 which show the features characteristic of the ,bennettitales1 agree closely with those of ,taenopteris vittata4 ,illustration3 ,fig4 #efi4 ,williamsoniella coronata4 ,vertical section of the flower showing the pyriform axis with small megasporophylls and interseminal scales and the microsporophylls with synangia4 7,after ,thomas2 #b47 ,illustration3 ,fig4 #egj4 ,williamsoniella coronata4 ,diagrammatic sketch of a microsporophyll in section and in side-view4 7,after ,thomas2 #c47 ,illustration3 ,fig4 #ega4 ,williamsoniella coronata4 ,a1 flower showing two microsporophylls and the central axis with megasporophylls4 ,b1 apical view of an unexpanded flower4 ,c1 flower-axis showing the shallow grooves made by the infolded microsporophylls1 which have fallen1 and a few megasporophylls1 s4 7,after ,thomas2 ,a1 #a2 ,b1 ,c1 #c47 ,illustration3 ,fig4 #egb4 ,williamsoniella coronata4 ,apical disc with megasporophylls and interseminal scales at the base4 7,after ,thomas2 #c47 ,the interseminal scales associated with the ovules and covering the pyriform axis above the microsporophylls are more or less flattened and hexagonal and the micropylar tubes often project far beyond the scales4 ,each micropyle-tube is surrounded by #e-f interseminal scales 7cf4 fig4 #efd74 ,the ovules differ from those of ,cycadeoidea ,gibsoniana in the absence of a distinct pedicel and agree with the corresponding organs of ,williamsonia scotica#acjb4 ,in the absence of epidermal papillae the micropylar tubes resemble those of ,wielandiella angustifolia4 ,as already stated1 the flowers appear to be without protective bracts1 but in the shale from which the specimens were obtained a few bract-like organs were discovered consisting of a lanceolate lamina #ae cm4 long1 and #b-c mm4 broad near the base1 and some showed a small oval lamina at the apex with a midrib and dichotomously branched lateral veins4 ,these bracts with the terminal lamina are regarded by ,thomas as almost certainly reduced leaves of the ,taeniopteris vittata type3 they are represented in the restoration 7fig4 #egc7 as occurring at the base of the flower-peduncle4 ,stomata were found on the bracts exactly like those on the microsporophylls1 and this affords a strong argument in support of the view that ,williamsoniella belongs to the plant which bore ,taeniopteris fronds4 ,there is a close parallelism between the bracts accompanying ,williamsoniella flowers and those described by ,nathorst in connexion with ,wielandiella#acjc4 ,it seems reasonable to regard the bracts as serving the purpose of bud-scales4 ,illustration3 ,fig4 #egc4 ,williamsoniella coronata4 ,restoration of part of a plant3 the upper leaves are represented only by the petiole-bases4 7,after ,thomas2 ca4 nat4 size47 ,an important point is the constant association with the flowers of ,taeniopteris vittata fronds1 a species described in ,vol4 ii4 and by most palaeobotanists regarded as a ,fern frond4 ,taeniopteris leaves occasionally show a clean-cut base#acjd and in specimens described by ,thomas there are two small humps on the surface of the proximal end of the petiole which represent vascular bundles4 ,humps of similar size occur on the leaf-scars of stems which are believed to have borne both ,taeniopteris leaves and ,williamsoniella flowers4 ,fragments of the stems were found in association with flowers3 they are #g mm4-#b cm4 in diameter and frequently forked and there is evidence that the flowers were borne at the forks1 the shoot forming a dichasial system4 ,the habit of the plant is represented in fig4 #egc reproduced from ,mr ,thomas's paper4 ,williamsoniella ,lignieri 7,nathorst74 ,this species described by ,nathorst as ,williamsonia8 ,lignieri from ,whitby is regarded by ,thomas as a ,williamsoniella4 ,the stomata on the microsporophylls agree with those of ,taeniopteris and the spores obtained from ,nathorst's flower-buds are like those of ,williamsoniella coronata4 ,evidence is adduced by ,thomas in favour of regarding ,w4 ,lignieri as bisexual and not unisexual as ,nathorst supposed4 ,in habit ,williamsoniella resembles ,wielandiella3 in the latter genus the foliage-leaves were confined to portions of the stem near the forks1 while in ,williamsoniella they were more uniformly scattered3 ,wielandiella bore leaves of the ,anomozamites form while ,williamsoniella flowers are always associated with ,taeniopteris fronds4 ,the much greater spore-output of ,williamsonia may1 it is suggested by ,thomas1 be correlated with the unisexual nature of the flowers of that species4 ,the microsporophylls of ,williamsoniella differ in their more reduced form from the pinnate microsporophylls of ,williamsonia1 e4g4 ,w4 spectabilis1 and agree more closely with those of ,wielandiella4 ,the microsporophylls of ,williamsoniella are free and not connate at the base as in ,cycadeoidea and ,williamsonia4 ,in its pyriform axis ,williamsoniella resembles ,williamsonia gigas and differs from ,williamsonia ,leckenbyi in the possession of a sterile apical corona3 ,williamsoniella has megasporophylls and microsporophylls both of which appear to be functional1 while in ,cycadeoidea fully developed microsporophylls occur in association with megasporophylls which are immature and must have matured much later than the microsporophylls4 ,the new genus agrees with ,williamsonia in its general features1 but the flowers are smaller and are characterised by the considerable reduction and simplification of the male organs4 ,,cycadocephalus4 ,nathorst4 ,this genus was founded#acje on a specimen from the ,lower ,rhaetic of ,scania1 at first regarded as a megastrobilus and on further examination#acjf found to be a collection of microsporophylls resembling those of ,williamsonia and ,cycadeoidea4 ,the type-species is ,cycadocephalus ,sewardi1 and a second species1 ,c4 minor1 was subsequently discovered by ,dr ,halle at a slightly higher horizon in the ,rhaetic series4 ,prof4 ,nathorst's most recent account of the genus affords a striking illustration of the possibilities of the method1 which he has employed with conspicuous success1 of investigating carbonised fossils by means of cuticular preparations4 ,illustration3 ,fig4 #egd4 ,cycadocephalus ,sewardi4 ,a1 surface-view2 a1 appendages4 ,b1 the same specimen1 after the removal of some of the microsporophylls1 showing the appendages4 ,c1 section of a microsporophyll showing the attachment of appendages4 ,d1 section of an appendage4 7,after ,nathorst4 ,a1 ,b1 nat4 size47 ,cycadocephalus ,sewardi ,nathorst4 ,the type-specimen consists of an oval cluster of #af-ah linear microsporophylls1 #i cm4 long1 springing from a small circular disc formed of their concrescent and narrow bases4 ,the whole flower 7fig4 #egd7 exclusive of the peduncle is #aj cm4 long and #g cm4 broad4 ,the portion of the comparatively slender peduncle that is preserved shows no trace of leaf-scars4 ,in the middle of each linear microsporophyll is a keel-like midrib and on either side of this is a series of linear appendages 7fig4 #egd7 #b-c cm4 long lying in a radial direction towards the centre of the flower4 ,these appendages were originally thought to be seeds 7fig4 #egd1 a71 but it was suggested by ,wieland that they might be synangia1 the circle of leaves being the male portion of a bisexual flower of the ,cycadeoidea type4 ,nathorst's more complete investigation of the specimen confirmed the first of these suggestions1 but there is no evidence that there was an ovulate receptacle in the centre of the flower4 ,the appendages are attached by a rather broad and slightly cordate base and are represented by a thin carbonised cuticle of rectangular cells showing in one case a row of imperfectly preserved stomata3 on this are numerous groups of tetrahedral microspores1 about #ee in diameter1 which show a more or less well marked arrangement in rows transverse to the long axis of the thin laminae4 ,it is clear from ,nathorst's researches that the groups were enclosed in loculi bounded by thin-walled cells#acjg1 the loculi being in transverse rows on each side of a midrib4 ,nathorst speaks of the appendages as synangia characterised by the large number of the sporogenous compartments1 and he compares them especially to the fertile leaflets of ,danaea elliptica as described by ,bower#acjh1 each appendage being comparable with a revolute ,danaea pinnule in which the edges of the lamina are united4 ,this is illustrated by the section of an appendage 7fig4 #egd1 ,d7 reproduced from ,nathorst's restoration of a ,cycadocephalus microsporophyll4 ,from a morphological point of view it would seem more appropriate to speak of the appendages as highly modified pinnules rather than synangia4 ,the second species1 ,c4 minor1 agrees closely except in its smaller size with the type-species4 ,nathorst regards ,cycadocephalus as a unisexual flower differing from those of ,williamsonia and from the microsporophyll-verticils of ,cycadeoidea in the structure of the synangia and in the tetrahedral form of the spores1 though the latter feature he considers to be of secondary importance1 as both bilateral and radial spores occur in recent ,marattiaceae4 ,he includes the genus in the ,bennettitales but suggests that it should be referred to a separate family as an indication of the possession of characters which mark it off from ,williamsonia1 ,weltrichia1 ,wielandiella1 and ,cycadeoidea4 ,,weltrichia4 ,braun4 ,the name ,weltrichia was given by ,braun#acji to some ,rhaetic fossils discovered by ,weltrich near ,culmbach in ,franconia which represent funnel-shaped structures1 the lower part having the form of an incomplete cup made of the concrescent bases of about #bj broadly linear segments which in the upper part are separate lanceolate lobes each with a midrib and slightly curved inwards at the apex4 ,the whole1 nearly #aj cm4 long and #i cm4 in diameter at the upper edge1 is very similar to the specimen of ,williamsonia spectabilis reproduced in fig4 #eea4 ,braun described three species1 but he realised the possibility that the different forms may be different stages in the development of a single type ,weltrichia mirabilis4 ,he assigned the genus to the ,rhinantheae4 ,saporta#acaj drew attention to the resemblance of ,braun's species to some examples of ,williamsonia from ,yorkshire which he considered to be portions of a sterile appendage borne at the apex of the flower4 ,some account is given of two types of funnel-like structures connected with ,williamsonia flowers on a previous page#acaa3 one of these has been shown by ,nathorst to be a whorl of microsporophylls1 and it is with this that ,weltrichia agrees4 ,an important feature of ,weltrichia is the occurrence of short linear segments1 #e-h mm4 long1 attached to the inner face of each of the free portions of the linear lobes3 the lobes1 or more correctly the free apical portions of the fertile leaves1 and their slender appendages are compared by ,nathorst#acab to the microsporophylls and relatively long synangia-bearing appendages of ,cycadocephalus4 ,these1 presumably fertile1 segments of ,weltrichia project in the flattened impressions beyond the edges of the free lobes of the campanulate flower and look like marginal teeth1 though they are actually attached on each side of the midrib and originally extended1 as in ,cycadocephalus1 towards the centre of the funnel-shaped flower4 ,the examination of one of the type-specimens acquired by ,nathorst#acac for the ,stockholm ,museum enabled him to confirm his earlier conclusion that ,weltrichia represents the male portion of a flower1 whether unisexual or bisexual cannot be definitely determined1 of a ,bennettitalean plant4 ,there is1 as ,nathorst states1 a close agreement in plan between ,weltrichia1 ,cycadocephalus1 and ,williamsonia1 and indeed it is not clear in what respects ,weltrichia is sufficiently distinct from ,cycadocephalus to be retained as a separate genus4 ,our knowledge of ,weltrichia is1 however1 less complete than in the case of ,cycadocephalus and ,williamsonia4 ,it is noteworthy that ,braun's specimens and those on which ,cycadocephalus was founded were obtained from ,rhaetic rocks4 ,an account of ,weltrichia has also been published by ,schuster#acad who differs from ,nathorst in his interpretation of the type-specimens3 he considers that another fossil described by ,braun and named by him ,palaeoxyris microrhombea is the central1 female1 portion of a ,weltrichia flower1 a view that is not supported by any substantial evidence4 ,the specimens referred by ,braun to ,palaeoxyris and afterwards transferred by ,schimper#acae to the genus ,lepidanthium are too obscurely preserved to be determined with any degree of confidence1 and their connexion with ,weltrichia is purely hypothetical4 ,with ,weltrichia ,schuster also connects the fronds known as ,otozamites brevifolius ,braun and some impressions of stems1 combining all in a restoration of a complete ,weltrichia plant which rests more on imagination than on fact4 ,attention has elsewhere#acaf been called to some wholly misleading and incorrect statements made by ,schuster which vitiate the value of his descriptions4 ,saporta#acag described a species of ,weltrichia1 ,w4 ,fabrei4 from ,french ,rhaetic strata at ,mende 7,lozre7 which bears at least a close superficial resemblance to ,williamsonia spectabilis1 and the same author founded another species1 ,weltrichia oolithica1 on a drawing by ,zigno of a specimen from ,jurassic rocks in ,italy2 but this appears to be too imperfect for accurate identification4 ,all that can be said as to the nature of ,weltrichia1 as illustrated by the type-species1 is that it represents a ,rhaetic example of a verticil of microsporophylls very similar to those of ,williamsonia and ,cycadocephalus1 if not generically identical with the latter form4 ,,chapter ,,xxxviii4 ,,cycadophyta4 ,i4 ,cycadean ,stems other than ,cycadeoidea4 ,most of the stems now under consideration are represented by casts or impressions and afford no information with regard to anatomical characters4 ,they are in many cases more slender and less tuberous than typical ,cycadeoideas1 and a few are characterised by an irregular form of branching1 as is shown in some specimens of pith-casts from ,wealden strata in ,tilgate ,forest figured by ,mantell#acah and now in the ,british ,museum4 ,the genus ,wielandiella#acai 7fig4 #eff7 is an altogether distinct type represented by flowers as well as vegetative organs4 ,several generic names have been proposed for ,cycadean stems agreeing with those of many recent ,cycads in the possession of an armour of persistent leaf-bases1 but distinguished from ,cycadeoidea in the absence of any fertile lateral shoots intercalated among the petiole-bases4 ,it is1 however1 impossible in most cases to give any satisfactory definition by which these genera can be distinguished from one another2 the characters employed by ,carruthers#acbj1 ,saporta#acba1 and other authors are of comparatively little importance as trustworthy criteria and to a large extent are merely the expression of different states of preservation or of differences in age4 ,attention has elsewhere been called to the absence of any clear dividing line between stems referred to ,bucklandia1 ,yatesia1 ,fittonia and ,cylindropodium4 ,the species ,cycadeoidea gigantea described on a previous page affords an instructive example of the difficulty of drawing a generic distinction between certain types of ,cycadean stems3 in habit1 in the form and structure of the leaf-bases1 and in the ramenta this species is identical with other species of ,cycadeoidea1 but it differs in the absence of lateral fertile shoots1 a feature that may have no morphological significance4 ,it has already been pointed out that the absence of flowers intercalated among the leaf-bases may simply mean that the plant had not reached the stage of flower-production1 or their absence may be due to some unfavourable conditions4 ,similarly the stems for which ,saporta proposed the generic name ,clathropodium agree in every respect with ,cycadeoidea except in the absence1 apparent or real1 of lateral flowering branches4 ,such types as ,clathropodium foratum ,sap4 and ,c4 sarlatense ,sap4#acbb1 the latter probably from ,upper ,jurassic beds and the former from an unknown locality1 should be included in the genus ,cycadeoidea4 ,the stem referred by ,saporta to his genus ,platylepis as ,p4 micromyela#acbc was originally assigned to ,cycadeoidea and more recently ,lignier has wisely adopted the original generic name4 ,the generic term ,bolpopodium1 also instituted by ,saporta#acbd1 is applied to small tuberous stems which appear to be identical with the ,cycadeoidea type4 ,having regard to the meagre data supplied by casts of stems preserved in various stages of defoliation1 and in view of the impossibility of drawing other than purely arbitrary generic distinctions1 it is preferable to employ one generic name in a liberal sense for stems that there is good reason to regard as plants that cannot reasonably be referred to ,cycadeoidea4 ,the name ,bucklandia is thus employed1 and a few examples are described in illustration of the external features of stems that are undoubtedly ,cycadean but in most cases readily distinguished from ,cycadeoidea4 ,there are substantial grounds for stating that plants which bore flowers of the ,williamsonia type possessed stems having the characters of ,bucklandia4 ,it should1 however1 be remembered that we cannot always draw a clearly defined distinction between flowers included in ,williamsonia and ,bennettites1 or ,cycadeoidea1 particularly when they are represented only by detached ovulate strobili as in ,cycadeoidea 7,bennettites7 ,morierei and ,williamsonia scotica4 ,,bucklandia4 ,presl4 ,bucklandia was proposed by ,presl#acbe for a plant described by ,mantell#acbf from the ,wealden of ,tilgate ,forest and compared by him to the ,euphorbiaceae and arborescent ,ferns2 the same generic name was given by ,robert ,brown in #ahcb to a recent member of the ,hamamelidaceae4 ,stokes and ,webb#acbg referred the same fossil to ,clathraria1 a name applied by ,brongniart#acbh to certain types of ,sigillarian stems and afterwards adopted by him for the ,tilgate ,forest species1 ,c4 ,lyelli4 ,presl #8with remarkable discrimination' recognised the ,cycadean nature of the specimen4 ,carruthers#acbi in his definition of ,bucklandia includes a statement as to the nature of the carpellary leaves and suggests that a cone associated with the stems may be a staminate strobilus3 the cone is undoubtedly a megastrobilus of an ,araucarian plant and there is no evidence with regard to the nature of either the male or female reproductive organs in the material that he describes though1 as already pointed out1 there are reasons for believing that ,williamsonia flowers were borne on branches of ,bucklandia stems4 ,the flowering shoots were not short and intercalated among the petiole-bases as in ,cycadeoidea with the strobili barely projecting beyond the surface of the leaf-base armour1 but they formed comparatively long branches1 sometimes forked1 at the apex of the main stem 7cf4 figs4 #eda-edc74 ,bucklandia is usually represented by casts1 from ,rhaetic to ,lower ,cretaceous strata1 differing from ,cycadeoidea in the absence of numerous axillary short fertile shoots1 in the more slender form and greater length of the stems1 and in the less uniform size of the persistent leaf-bases which assume various forms4 ,some of the specimens reach a length of #d feet and afford evidence of occasional branching3 the surface is covered with leaf-bases preserved as imbricate1 broad1 and obtuse or truncate scales 7fig4 #ege71 or as slightly convex polygonal areas in some cases showing a tendency towards an irregular zonal arrangement of larger and smaller leaf-bases 7fig4 #egf74 ,within the armour of leaf-bases there may be a cast of the large pith the surface-features of which are practically identical with the cast of a recent pith reproduced in fig4 #cih4 ,casts of the pith preserved as separate fossils are included in the genus ,cycadeomyelon4 ,there is evidence of the occurrence of more than one zone of vascular tissue in a stem from ,lower ,greensand beds of ,bedfordshire described by ,carruthers as ,yatesia ,morrisii#accj 7 ,bucklandia ,yatesii71 and ,dr ,stopes#acca has recently described a species1 ,b4 buzzardensis 7fig4 #egh71 with several zones of conducting tissue4 ,this feature has not so far been satisfactorily demonstrated in ,cycadeoidea4 ,an ,indian species1 ,bucklandia indica1 shows that the secondary xylem is more compact than in typical ,cycadeoidea stems1 and the tracheids have multiseriate pitting4 ,two long and narrow stems figured by ,nathorst from the ,rhaetic of ,scania as ,bucklandia ,saportana#accb differ from other species in the irregular arrangement of the leaf-bases which in certain regions are crowded as in the typical example of the genus shown in fig4 #egf1 but in the intervening portions of the stem they are few in number and widely separated by the finely striated bark4 ,this type1 though similar to some specimens of ,english1 ,mexican1 and ,indian ,bucklandias in the zonal differences in the leaf-bases1 represents an extreme case of the alternation of smaller and crowded and larger and scattered leaf-scars4 ,it is by no means unlikely that ,bucklandia ,saportana forms a transition between ,bucklandia and the stem of ,wielandiella described by ,nathorst from the same region3 in ,wielandiella the leaf-scars are concentrated at the region of forking but a few occur elsewhere3 in ,b4 ,saportana there is no evidence of branching and in this respect it differs from ,wielandiella4 ,bucklandia anomala 7,stokes and ,webb74 ,this species1 from ,wealden beds in ,sussex1 was first described by ,stokes and ,webb#accc as ,clathraria anomala1 and the same type was figured by ,mantell and other authors as ,clathraria ,lyelli4 ,the specimens referred by ,carruthers to ,bucklandia anomala and ,b4 ,mantelli#accd do not exhibit any well defined specific differences1 and there would seem to be no reason for retaining both specific names4 ,the petiole-bases are usually sub-rhomboidal in form and convex or flat1 but in some stems more of each petiole is preserved and the surface is covered with broad imbricate scales 7fig4 #ege7 similar to some of the detached scales described under the generic name ,cycadolepis4 ,pith-casts occur both in connexion with the ,bucklandia stems and as detached specimens4 ,the leaf-bases often show an irregular zonation of smaller and larger rhomboidal areas4 ,the pith-cast in the lower part of the specimen from the ,wealden of ,cuckfield in ,sussex shown in fig4 #ege is #e #ce cm4 in diameter4 ,illustration3 ,fig4 #ege4 ,bucklandia anomala4 7,british ,museum1 ,no4 ,v4 #cfij2 rather less than natural size47 ,bucklandia ,ruffordi ,seward4 ,this species1 from the ,wealden beds on the ,sussex coast#acce1 was originally described as ,fittonia ,ruffordi1 but in the absence of any well defined distinctive features that can be regarded as of morphological significance it is better to include it in ,bucklandia4 ,the species affords a good example of a long and narrow type of stem1 one specimen reaching a length of nearly #hj cm4 with a breadth of about #aj cm42 the surface is covered with persistent leaf-bases #ag cm4 in depth with a scar agreeing in size and shape with the base of a frond of ,otozamites ,goeppertianus 7,dunk47#accf found in the same beds4 ,there is no indication of any alternation of large and small leaf-bases1 and the species is characterised by the uniform size and relatively greater depth in a vertical direction of the leaf-base areas4 ,in all probability the stem bore fertile branches similar to those of ,williamsonia gigas with flowers of the ,williamsonia type3 the fronds may have been those known as ,otozamites ,goeppertianus1 but this has not been demonstrated4 ,a stem described by ,carruthers from the ,lias of ,lyme ,regis as ,yatesia gracilis#accg and afterwards included by me in ,cycadeoidea#acch is very similar to ,b4 ,ruffordi in its long and narrow form and in the shape of the leaf-bases2 it should be transferred to ,bucklandia as ,b4 gracilis 7,carr474 ,bucklandia ,milleriana ,carruthers4 ,this species was founded on a cast from ,lower ,oolite beds at ,brora in ,sutherlandshire#acci characterised by leaf-bases very similar to those of ,b4 anomala but smaller4 ,casts from the same locality were named by ,carruthers ,yatesia crassa and ,y4 ,joassiana#acdj1 but an examination of specimens in the ,dunrobin ,museum leads me to regard these forms as indistinguishable from ,b4 ,milleriana4 ,the specimen reproduced in fig4 #egf from the ,great ,oolite of ,brora illustrates the external characters of a typical stem and shows the variation in the size of the leaf-bases4 ,a portion of the pith-cast is exposed in the lower part of the stem4 ,illustration3 ,fig4 #egf4 ,bucklandia ,milleriana4 ,brora1 ,scotland4 7,manchester ,museum1 ,l4 #gbbi4 ca4 nat4 size47 ,bucklandia ,yatesii 7,carruthers74 ,this type from the ,lower ,greensand of ,bedfordshire 7fig4 #egg7 was described by ,carruthers as ,cycadeoidea ,yatesii and subsequently named ,yatesia ,morrisii#acda4 ,ward expressed the opinion that the name should be ,yatesia ,yatesii1 but as ,bucklandia is now used to include ,yatesia this combination is fortunately avoided4 ,the stem is cylindrical1 #bj-cj cm4 long and #ab cm4 in diameter1 covered with rhomboidal leaf-bases separated from one another by a ramental reticulum4 ,there are two concentric vascular cylinders as stated by ,carruthers4 ,in a recent account of this species ,dr ,stopes#acdb adds further details3 the xylem-cylinders are #e-h mm4 wide and the tracheids occur in single rows or there may be bands #d-e elements broad2 the circular bordered pits are uniseriate or in two alternate series4 ,the medullary rays are broad but the cells are not preserved4 ,the pith-cast is of the usual ,cycadean type4 ,illustration3 ,fig4 #egg4 ,bucklandia ,yatesii4 ,type-specimen in the ,british ,museum4 ,the type-specimen was presented by the ,cirencester ,college to the ,british ,museum4 ,bucklandia buzzardensis 7,stopes74 ,illustration3 ,fig4 #egh4 ,bucklandia buzzardensis4 ,rough sketch of a block of wood showing parts of at least eight concentrically arranged rings of secondary wood4 7,after ,stopes2 47 ,this species1 from ,lower ,greensand beds at ,leighton ,buzzard and believed to be derived from ,wealden strata1 is described by ,dr ,stopes#acdc as ,cycadeoidea buzzardensis4 ,though agreeing generally with ,b4 ,yatesii1 the stem is specifically separated on the ground that the petiole-bases are more expanded laterally and because of the occurrence of several vascular cylinders 7fig4 #egh71 sometimes as many as eight1 each with a maximum diameter of #a cm4 ,dr ,stopes thinks it possible that ,b4 buzzardensis is an older form of ,b4 ,yatesii4 ,bucklandia squamosa 7,brongniart74 ,sternberg first described this species as ,conites ,bucklandi#acdd and regarded it as a cone bearing large imbricate cone-scales2 it was named by ,brongniart ,bucklandia squamosa#acde and ,carruthers#acdf retained this designation4 ,the type-specimen1 in the ,oxford ,museum1 from the ,stonesfield ,slate is #ah cm4 long1 showing in the lower part a cast of the pith4 ,the surface of the stem is covered with thick imbricate petiole-bases very like those on the stem of a recent ,encephalartos4 ,bucklandia 7,fittonia7 squamata 7,carruthers74 ,carruthers#acdg founded the genus ,fittonia on a single specimen from the ,wealden beds of the ,isle of ,wight1 separating it from ,bucklandia on the ground of the occurrence on a portion of the stem of large imbricate leaf-bases which are at first reflexed and then ascending2 the stem is also broader and more tuberous than most species of ,bucklandia4 ,the type-specimen1 in the ,museum of the ,geological ,survey 7,jermyn street71 bears a close resemblance to a trunk of a recent ,encephalartos1 but the part of the stem from which the imbricate stumps have fallen is practically identical with a ,bucklandia4 ,as in certain recent ,cycads the surface-features probably changed with the age of the plant2 when the foliage-leaves were first shed a portion of the ascending petiole remained on the stem1 and at a later stage this was cut off leaving a clean-cut rhomboidal scar like those on the ,bucklandia shown in fig4 #egf4 ,the difference between ,fittonia and ,bucklandia may1 therefore1 be a question of age4 ,while substituting ,bucklandia for ,fittonia as the generic name the latter designation is added in parentheses to denote the possession of certain features which1 though possibly of generic value1 are not regarded as sufficiently important morphologically to warrant generic recognition4 ,the type-specimen of ,saporta's species ,fittonia insignis#acdh1 in the ,paris ,museum1 from the ,oxfordian of ,poitiers1 appears hardly distinguishable from ,f4 squamata ,carr4 ,another type with broader imbricate petiole stumps is described by ,saporta from the ,portlandian near ,boulogne as ,fittonia ,rigauxi#acdi4 ,illustration3 ,fig4 #egi4 ,bucklandia indica4 ,a1 side-view showing the leaf-bases and attached petioles of ,ptilophyllum1 also 7to the left7 a fragment of a detached ,ptilophyllum leaf4 ,b1 transverse section showing the pith1 xylem cylinder1 cortex1 and sections of petioles4 7,british ,museum2 nat4 size47 ,bucklandia indica sp4 nov4 ,oldham and ,morris#acej and subsequently ,feistmantel#acea described some specimens of ,cycadean stems from the ,rajmahal ,hills of ,india of ,lower ,jurassic age3 the latter author regarded them as stems of ,williamsonia because of their association with flowers of that type1 a conclusion fully justified by the evidence4 ,feistmantel also called attention to the resemblance of the ,indian stems to specimens described from ,british strata as ,bucklandia and ,yatesia4 ,although the ,indian examples are very similar to stems from ,mexico discovered by ,wieland#aceb and to some of the ,english types1 it seems desirable to refer to them under a specific name and ,i therefore suggest the institution of the specific name indica1 the type-specimen being that represented in fig4 #egi4 ,this specimen is particularly interesting because it affords some information as to anatomical features and is one of the few fossil stems preserved in organic connexion with leaves 7fig4 #egi1 ,b74 ,a short account of it was published in #aijjacec and more recently ,miss ,bancroft#aced has made a fuller investigation of this and other ,indian specimens4 ,the stem shown in fig4 #egi from the ,rajmahal ,hills1 and now in the ,british ,museum1 bears fronds of ,ptilophyllum cutchense ,morr41 a type that appears to be indistinguishable from ,p4 pecten2 and with similar stems from the same beds are associated flowers of ,williamsonia4 ,miss ,bancroft describes a bract-covered shoot which agrees very closely with those of ,english stems reproduced in figs4 #eda1 #edb4 ,in addition to the evidence based on close association1 there is the more important argument furnished by the discovery of ramental hairs like those on the bracts of ,williamsonia scotica and of anatomical characters in the bracts similar to those in the ,scotch strobilus4 ,the persistent leaf-bases are far from uniform in size2 in this respect and in their form they agree closely with those on ,bucklandia stems from ,english and ,mexican localities4 ,the secondary wood is more compact than in recent ,cycads or in ,cycadeoidea1 though it resembles that of ,cycadeoidea micromyela2 the medullary rays are uniseriate and the tracheids have multiseriate bordered pits on their radial walls instead of the scalariform pitting in the majority of ,cycadeoidea stems4 ,secretory canals are abundant in the parenchymatous ground-tissue2 the cambium and phloem are not preserved#acee4 ,the transparent nature of the silicified material rendered very difficult the examination of the tissues1 but enough was discovered to show that these ,indian stems are characterised by certain features1 the more compact nature of the secondary xylem and the presence of multiseriate pitting1 which distinguish them from the ,cycadeoidea type4 ,further knowledge of the anatomical features of the ,williamsonia 7,bucklandia7 stems from other localities might enable us to recognise these or other peculiarities as constant distinguishing characters of ,bucklandia in contrast to the ,cycadeoidea stems which bore the ,bennettites type of flower4 ,cycadeomyelon4 ,saporta4 ,casts of the pith-cavity of ,cycadean stems1 like that shown in fig4 #ege projecting beyond the armour of leaf-bases1 are occasionally found as separate fossils and cannot always be referred to a particular species of stem4 ,for such detached casts ,saporta#acef instituted the name ,cycadeomyelon3 they are characterised by their comparatively large diameter and by the possession of surface-features similar to those on the corresponding cast from a recent ,cycadean stem shown in fig4 #cih1 namely spirally disposed1 more or less prominent1 lozenge-shaped areas formed by the sand or mud filling the cavities left on the decay of the parenchyma of the broad medullary rays of a manoxylic stem4 ,occasionally a slit at the lower end of a medullary ray area marks the position of the leaf-trace bending outwards from the lower angle of the mesh in the xylem-lattice#aceg4 ,lignier figures part of a pith-cast of ,cycadeomyelon ,apperti#aceh in which each medullary-ray area has a circular depression and not a slit extending from the lower angle3 this may indicate that the surface shown on the cast is slightly external to the inner edge of the stele and in a plane where the leaf-traces were embedded in the parenchyma of the rays and free from the xylem-cylinder4 ,large and branched examples of ,cycadeomyelon were figured by some of the earlier authors from ,english ,wealden beds as species of ,clathraria#acei and in many cases these are undoubtedly pith-casts of ,bucklandia stems3 a similar cast is figured under this name by ,schenk from the ,wealden of ,north ,germany4 ,from ,liassic beds in ,normandy ,lignier figures two species of ,cycadeomyelon1 ,c4 ,apperti and ,c4 densecristatum4 ,the surface-features of ,cycadeomyelon resemble those of the ,palaeozoic genus ,tylodendron 7see ,vol4 iv471 but in the latter genus the nodal swellings are a characteristic peculiarity4 ,though medullary casts of this type are of no great botanical importance and their specific distinctions are of little value1 it is safe to assume that broad medullary casts with comparatively large lozenge-shaped areas belong to ,cycadean stems1 while narrower specimens with smaller lozenges are more likely to be pith-casts of ,coniferous stems4 ,lester ,ward#acfj instituted the genus ,feistmantelia for some ,lower ,cretaceous casts from the ,black ,hills which he compared with an ,indian fossil from ,cutch described by ,feistmantel as #8the stem of a ,coniferous plant#acfa1' and with pith-casts figured by ,stokes and ,webb as ,clathraria anomala4 ,it is impossible to determine the systematic position of such imperfect specimens as that on which ,ward founded his species ,f4 oblonga3 they may1 as ,hollick and ,jeffrey#acfb suggest1 be casts of the bark of some ,conifer2 there is certainly no good reason for connecting them with ,cycads4 ,,colymbetes4 ,stopes4 ,colymbetes ,edwardsi ,stopes4 ,this genus#acfc is founded on the inner portion of a petrified trunk which was probably cylindrical and more than #ab cm4 in diameter1 consisting of a pith1 #ge cm4 in diameter1 and part of a vascular cylinder of remarkable structure4 ,the type-specimen is of ,aptian age and may have come from ,leighton ,buzzard 7,bedfordshire74 ,the pith 7fig4 #ehj1 p7 consists of large parenchymatous cells and numerous secretory canals3 the perimedullary zone1 pm1 is characterised by the occurrence of loosely disposed tracheids in groups and radial rows pursuing a sinuous longitudinal course in the accompanying parenchyma4 ,the tracheids in this region are small in diameter and have oval1 scalariform1 or circular pits4 ,abutting on the perimedullary zone is the secondary xylem the inner edge of which forms bays1 and this is composed of alternating zones of vertical and horizontal tracheids 7fig4 #ehj1 y-x2 fig4 #eha7 with bordered1 scalariform1 pits on their walls traversed by medullary rays generally biseriate and from #d to #cj cells deep4 ,the disposition of the tracheids is such as to render transverse and radial longitudinal sections practically identical in appearance2 the first zone of secondary xylem with its bayed inner edge consists of vertically running elements2 this is succeeded by a zone in which the tracheids pursue a horizontal course1 and beyond this second zone is another band of vertical elements 7fig4 #eha74 #8,where the one zone passes into the next1 a curving of the elements is frequently evident1 and in a few cases it is quite possible to trace a single radial series of tracheids through an angle of #ij running in the same section1 first as a transverse and then as a vertical series4 ,one and the same medullary ray also can sometimes be followed1 first in transverse and then in radial longitudinal section1 which later again turns to true transverse4 ,the inference is therefore drawn that there was but a single cambium1 which had periodic changes of direction4' ,leaf-traces 7fig4 #ehj1 lt7 are large and numerous2 they are spirally disposed and pass nearly straight through successive xylem-zones3 each trace consists of a small-celled ground-tissue including stone-cells and patches of tracheids in more or less regular radial rows4 ,tangential sections of the wood show that the tracheids follow a sinuous course forming loops enclosing numerous medullary rays4 ,illustration3 ,fig4 #ehj4 ,colymbetes ,edwardsi4 ,transverse section showing ten alternating zones of wood outside the perimedullary zone1 pm2 y1 y1 etc41 vertically running xylem series2 x1 x1 etc41 horizontally running xylem series2 p1 pith2 lt1 leaf-traces4 7,after ,stopes2 #b47 ,illustration3 ,fig4 #eha4 ,colymbetes ,edwardsi4 ,diagram of stem in transverse 7,a7 and radial longitudinal 7,b7 section4 p1 pith2 pm1 perimedullary xylem2 b1 bays of first1 vertically running1 secondary xylem2 x1 x1 etc41 zones of horizontally running secondary xylem cut transversely in the radial and radially in the transverse section of the stem2 y1 y1 etc41 longitudinally running xylem cut transversely in the transverse and longitudinally in the radial section4 7,after ,stopes47 ,as the pith and xylem are the only tissues preserved it is on their structure that any speculation as to affinity must be based4 ,the close arrangement of the leaf-traces 7about #a cm4 apart71 as ,dr ,stopes says1 indicates small leaf-bases1 assuming that each leaf received a single trace4 ,in some respects the xylem and medullary rays resemble those of ,cycads1 and the author of the genus includes it in the ,cycadophyta2 but as she points out there are many peculiar features1 and it is clearly impossible to assign the new type to a more precisely defined position4 ,the possibility of any purely mechanical explanation of the course of the tracheids in the alternating zones is ruled out by the straight course of the outgoing leaf-traces1 and it would seem that the cambium must have turned over at right-angles at regular intervals during the growth of the stem4 ,cycadolepis4 ,saporta4 ,this name was used by ,saporta#acfd for linear-lanceolate scales from ,upper ,jurassic rocks in ,france which he compared with bud-scales of recent ,cycads4 ,the imperfect scale described as ,cycadolepis villosa bears a striking resemblance to the hairy bracts of ,williamsonia and may well belong to that genus4 ,saporta's term may be usefully employed in a more extended sense1 including not only lanceolate scales but larger and much broader scales resembling the flattened petiole-bases on stems of ,macrozamia1 ,encephalartos1 and some other recent genera1 as well as detached carpellary scales1 other than ,cycadospadix1 and microsporophylls which cannot be assigned to a particular stem4 ,two qualifying subgeneric terms have been proposed#acfe3 i4 ,cycadolepis 7,dory-,cycadolepis74 ,scales more or less linear-lanceolate like those described by ,saporta and a specimen from ,jurassic rocks of ,india named by ,feistmantel#acff ,cycadolepis pilosa4 ,this type of ,cycadolepis may be identical with the bracts of ,williamsonia flowers1 though in the absence of any definite evidence of such affinity the provisional generic name is more appropriate4 ii4 ,cycadolepis 7,eury-,cycadolepis74 ,broadly oval or orbicular thick scales 7figs4 #ehb1 #ehc71 the broadest part being frequently nearer the distal than the proximal end4 ,these larger scales though usually found as detached fossils have in one instance been obtained attached to an imperfectly preserved stem4 ,illustration3 ,fig4 #ehb4 ,cycadolepis 7,eury-,cycadolepis7 sp4 ,from the ,wealden beds of ,sussex4 7,brit4 ,mus4 ,no4 ,v4 #bgii47 ,illustration3 ,fig4 #ehc4 ,cycadolepis 7,eury-,cycadolepis7 sp4 ,scale from the ,wealden beds of ,sussex4 7,british ,museum1 ,no4 ,v4 #baca;a2 nat4 size47 ,eury-,cycadolepis sp4 ,this type of scale1 represented by specimens from the ,wealden of ,sussex#acfg 7figs4 #ehb1 #ehc71 reaches a length of #ac cm4 and a breadth of #g cm4 and is sometimes almost orbicular4 ,the lamina is convex but shows no definite venation and bears a close resemblance to the scale-like petiole-stumps on an old stem of ,macrozamia4 ,on some of the smaller specimens 7fig4 #ehc7 several forked veins extend vertically from the broad base4 ,since these specimens were first described additional examples have been discovered in the ,wealden beds of ,sussex1 some of which are attached to a piece of stem#acfh in such a manner as to give support to the view that they are leaf-bases very similar to those on such fossil stems as ,bucklandia 7,fittonia7 ,rigauxi 7,sap47#acfi and ,b4 7,fittonia7 squamata 7,carr47#acgj4 ,one partially carbonised scale yielded pieces of cuticle showing numerous stomata similar to those of recent ,cycads and the outlines of very thick-walled epidermal cells#acga4 ,eury-,cycadolepis ,jenkinsiana 7,tate74 ,the large and approximately orbicular or broadly ovate scales so named are believed to be identical with ,tate's ,cyclopteris ,jenkinsiana#acgb from the ,uitenhage series of ,cape ,colony 7,wealden74 ,the scales reach a length of #ab cm4 and were attached by a broad base2 the lamina1 which may be strongly bent as though folded over some immature organ as a protective bract1 shows numerous repeatedly forked veins of the ,cyclopteris type and several anastomosing and irregular lines between the veins suggesting that the scales were tomentose4 ,,ii4 ,reproductive ,organs of ,cycadean ,plants other than those of the ,bennettitales4 ,the fact that practically all known ,cycadean stems bore flowers either of the ,bennettites or ,williamsonia type prepares us for the scarcity of reproductive organs like those of recent ,cycads4 ,no specimens have been discovered in a petrified state affording any evidence of their close affinity to the cones1 sporophylls1 or seeds of the ,cycadales4 ,such genera as ,cycadospadix1 ,androstrobus1 and ,zamiostrobus1 as the following descriptions show1 are founded on material that is too imperfect to throw much light on their true morphological nature4 ,the probability is that some at least of the specimens included in these genera are the reproductive organs of ,cycadean plants more closely allied to the existing ,cycads than to the ,bennettitales4 ,among the numerous fossil seeds referred to such genera as ,cycadeospermum and ,cycadinocarpus there are but few that can confidently be assigned to the ,cycadales rather than to the ,ginkgoales or ,coniferales4 ,while the seeds of the ,bennettitales are clearly distinguished by their much smaller size from those of modern ,cycads1 many of the latter agree in size and form with those of some other ,gymnosperms and in the absence of anatomical details could not easily be identified as fossils4 ,some of the examples included in the miscellaneous collection described by authors as species of ,carpolithus or ,carpolithes agree closely in external features with the seeds of modern ,cycads1 but it is seldom possible to accept them as undoubted records of ,cycadalean plants4 ,the general conclusion is that such meagre evidence as we possess affords strong confirmation of the conclusion based on stems and foliage from ,jurassic and ,cretaceous strata1 namely that the present representatives of the ,cycadophyta are a relatively late product of evolution1 though retaining in their anatomical features many survivals from a remote antiquity4 ,the occurrence of ,cycadean characteristics in the vegetative organs of the ,medulloseae and the recurrence of what may be called the ,cycadean seed-plan1 with certain more or less striking peculiarities reminiscent of earlier stages of evolution1 in several types of ,palaeozoic seeds such as ,cycadinocarpus1 ,stephanospermum1 ,lagenostoma and others bear testimony to the antiquity of the ,cycadean stock4 ,,carpolithus#acgc4 ,linnaeus4 ,this generic name1 as ,nathorst#acgd has recently pointed out1 was used by ,linnaeus in #agfh for #8,phytolithus fructus' and has therefore priority over ,sternberg's genus ,carpolites employed in #ahbe4 ,lester ,ward#acge attributes ,carpolithus to ,stokes and ,webb 7#ahbd7 and states that in the plural form the name was used by ,walch in #agga4 ,carpolithus is a convenient term to apply to fossil seeds that cannot be assigned to a particular group of plants and which do not exhibit any peculiarities of form sufficiently striking to deserve generic recognition4 ,pomel#acgf proposed the genus ,ulospermum but it never came into general use4 ,schimper's genus ,cycadinocarpus and ,saporta's ,cycadeospermum 7preferable in its morphological implication71 though useful in the case of detached seeds of undoubted ,cycadean affinity1 can seldom be employed without an admission that they may imply a relationship that cannot be absolutely established4 ,in the great majority of cases the better plan is to be content with the more non-committal term ,carpolithus with the addition of a family-name when there are reasonably good grounds for a more definite reference4 ,no useful purpose would be served by attempting a complete survey of the numerous casts and impressions of supposed ,cycadean seeds recorded in palaeobotanical literature1 but a few types are briefly described as examples of specimens with fairly well defined characters1 which are in all probability ,cycadean4 ,carpolithus conicus 7,cycadales87 ,lindley and ,hutton4 ,illustration3 ,fig4 #ehd4 ,carpolithus conicus4 ,the type-specimens in the ,manchester ,museum2 nat4 size4 7a1 ,no4 #cfa2 b1 c1 ,no4 #cfj47 ,illustration3 ,fig4 #ehe4 ,carpolithus conicus4 ,from a specimen in the ,malton ,museum2 nat4 size4 ,the original specimen figured by ,lindley and ,hutton#acgg from the ,coralline ,oolite of ,malton1 ,yorkshire1 as ,carpolithes conica and now in the ,manchester ,museum1 is represented in fig4 #ehd4 ,a second #8species1' ,carpolithus ,bucklandi ,lind4 and ,hutt4 ex ,will4 ,,ms4#acgh1 from the same locality is no doubt specifically identical with ,c4 conicus4 ,the seeds are conical1 broadly truncate at one end1 presumably the base1 and tapered to a blunt apex2 the broad end is characterised by the presence of three ridges or in some specimens by a single median ridge illustrating an oscillation between the radiospermic and platyspermic form similar to that in ,ginkgo biloba4 ,as usually obtained the seeds are probably nucules or casts showing the surface-features of the inner wall of the sclerotesta1 the sarcotesta having been destroyed before fossilisation3 the irregular marginal teeth at the truncate end suggest casts of vascular bundles in the integument4 ,the scattered tubercles on the sides of some of the seeds 7fig4 #ehd1 a7 are probably casts of holes in the shell bored by insects and comparable with those occasionally preserved on the casts of ,trigonocarpus4 ,a specimen in the ,malton ,museum shown in fig4 #ehe which may be an example of this species illustrates the occurrence of an internal cast enclosed by the remains of a thick testa4 ,these ,jurassic casts resemble the seeds of ,macrozamia ,fraseri1 but it is impossible to determine their systematic position with confidence4 ,carpolithus sp4 7,cycadales87 ,seward4 ,an unusually well preserved specimen from the ,wealden beds of the ,sussex coast described under this name in #ahieacgi consists of a kernel and mould1 #ah #aa cm4 ,the mould from which the kernel is readily removed is lined with a thin structure representing part of the testa and between this and the surrounding rock is a layer of coal4 ,on the surface of the kernel1 probably the cast of the seed-cavity1 a reticulum of narrow grooves indicates the course of the vascular bundles over the surface of the nucellus4 ,carpolithus 7,cycadales87 ,pomelii 7,saporta74 ,the specimen from the ,upper ,corallian of ,chteauroux 7,indre7 on which this species was founded by ,saporta#achj under the name ,cycadeospermum ,pomelii is a large ovate cast1 #ee cm4 long and #ce cm4 broad1 closely resembling some of the larger recent ,cycadean seeds3 it cannot be accepted as a true record of the group without reservation4 ,saporta describes other species of ,cycadeospermum but none of them are of any real importance from a botanical point of view3 the same remark applies to the seeds referred by ,fontaine#acha from ,potomac beds to the same genus1 also to many other recorded examples of seeds that afford no decisive evidence of affinity4 ,some specimens described by ,compter#achb from the ,lettenkohle of ,apolda 7,thuringia7 as ,cycadean fruits--too imperfect to be determined with accuracy--furnish an additional illustration of the slender foundation on which many of the records of supposed ,cycadean reproductive organs are based4 ,,cycadospadix4 ,schimper4 ,this name was proposed by ,schimper#achc for some ,french ,jurassic fossils1 described by ,pomel#achd as ,crossozamia ,hennocquei and ,c4 ,moraeana1 on the ground that they bear a close resemblance to the megasporophylls of ,cycas4 ,their occasional association with ,otozamites fronds suggested a reference to the same parent-plant1 but such data as we have point to ,otozamites fronds having been borne by plants with the ,williamsonia type of flower4 ,schenk#ache1 who figured a specimen of ,cycadospadix from ,france as the inflorescence of a ,cycad1 expresses the more probable opinion that it belonged to a plant with ,cycadites fronds4 ,a ,permian species described by ,renault as ,cycadospadix ,milleryensis is now transferred to the genus ,strobilites#achf4 ,cycadospadix ,pasinianus ,zigno4 ,this species1 first described from ,jurassic strata in ,northern ,italy#achg1 is recorded also from the ,kimmeridgian of ,france#achh and ,scotland#achi4 ,zigno's figures give a fairly accurate representation of the type-specimens in the ,padua ,museum4 ,the megasporophylls1 almost identical in shape with those of some recent species of ,cycas 7figs4 #cha2 #cib1 ,a-,c71 consist of a broadly lanceolate or triangular limb with deeply laciniate sides terminating a pedicel1 or the distal expansion may be preserved without the stalk from which it was no doubt easily detached as in certain recent ,cycads 7cf4 fig4 #cib1 ,a74 ,in the specimen from ,scotland there are no clear indications of veins in the lamina1 which may have been woolly as in ,cycas4 ,in some of the specimens figured by ,saporta#acij and now in the cole des ,mines1 ,paris1 the stalk is absent1 but in pedicellate examples scars occur on the sides of the narrow axis and casts of seeds are found in the same beds4 ,a good example of ,cycadospadix ,hennocquei is figured by ,saporta from a drawing supplied by ,schimper showing two seed-scars near the base of the lamina3 the same specimen1 as figured by ,saporta and ,marion#acia1 bears a seed1 but this is presumably a partial restoration4 ,the occurrence of ,cycadites rectangularis ,brauns at ,hettange in association with ,cycadospadix strengthens the conclusion1 based on the form of the megasporophylls1 that some of the ,jurassic ,cycads bore megasporophylls very similar to those of existing species of ,cycas4 ,cycadospadix integer ,nathorst4 ,this ,rhaetic species from the south of ,sweden#acib was instituted for an imperfect broadly lanceolate lamina recalling the distal end of the megasporophyll of a ,cycas3 the discovery of a more complete example#acic justifies ,nathorst's use of the name ,cycadospadix1 though without further evidence one hesitates to regard the species as a thoroughly trustworthy record of a ,cycadean fertile leaf4 ,the species is characterised by the entire margin of the broad and relatively short and thick terminal limb borne on a broad stalk with alternate lateral projections presumably marking the position of the seeds4 ,these species of ,cycadospadix are particularly interesting as evidence--though not amounting to demonstration--of the production by some ,jurassic and ,rhaetic plants of fertile leaves agreeing closely with those of ,cycas4 ,it would seem from the abundance of ,bennettitalean flowers and the very scanty remains of fertile leaves or cones like those of modern ,cycads that the existing type was exceptional in ,mesozoic floras4 ,,beania4 ,carruthers4 ,beania gracilis ,carruthers4 ,illustration3 ,fig4 #ehf4 ,beania gracilis4 7,after ,carruthers2 nat4 size47 ,the generic name ,beania#acid was given to a branched fertile shoot 7fig4 #ehf7 from the ,middle ,jurassic beds at ,gristhorpe1 ,yorkshire1 characterised by loosely disposed sporophylls bearing two sessile seeds3 each sporophyll is given off at a wide angle from a fairly stout axis and the seeds are borne on the adaxial side of a peltate distal expansion4 ,carruthers compared the type-species with a cone of ,zamia with which it agrees in the general plan of construction but differs in the more open habit and in the longer and more slender seed-bearing pedicels4 ,the same type of shoot was figured by ,lindley and ,hutton#acie as ,sphaereda paradoxa4 ,beania is generally regarded as a ,cycadean reproductive shoot1 but there is no doubt that the majority of ,jurassic ,cycadophyta possessed flowers of the ,bennettites types1 and it is clear that ,beania differs considerably from ,bennettites and ,williamsonia4 ,another suggestion is that ,beania may belong to some member of the ,ginkgoales#acif3 though very different from the normal ovuliferous shoot of a ,ginkgo1 it resembles some abnormal forms 7e4g4 fig4 #fca1 ,d7 in which the ovules occur on elongated pedicels1 but they are borne singly and the micropyle is directed outwards1 while in ,beania the ovules are attached in pairs to the inner face of a distal expansion4 ,there is no conclusive evidence in support of either interpretation1 though the general agreement between the ,jurassic type and the cones of recent ,cycads would seem to favour the inclusion of ,beania among the ,cycadophyta4 ,a specimen described by ,nathorst#acig from ,upper ,jurassic rocks in the ,north of ,scotland as ,beania ,carruthersi closely resembles the type-species1 differing chiefly in its smaller size and in the rather closer arrangement of the sporophylls4 ,the seed-like bodies borne in pairs on the adaxial side of the terminally expanded pedicels are covered with small granulations which ,nathorst thinks may be clusters of microspores1 the apparent seeds being #8antherangia4' ,the granulations are1 however1 very similar to those on the larger detached seed-like bodies originally described by ,nathorst from ,rhaetic beds in ,sweden as ,antherangiopsis rediviva#acih3 subsequent examination of that species demonstrated that the granulations are due to the presence of resinous bodies in the tissues of true seeds#acii1 and it is not improbable that a similar interpretation may hold for the surface-features in the supposed male organs of ,beania ,carruthersi4 ,pending further evidence it may be suggested that ,beania ,carruthersi is like ,b4 gracilis a seed-bearing shoot4 ,the ,rhaetic specimens described by ,nathorst as ,stenorrachis scanicus#adjj are similar in habit to ,beania but differ in the forking of the sporophylls 7fig4 #fef7 and in the absence of any terminal swelling on which the seeds are borne3 ,nathorst considers that ,stenorrachis may be the female organ of a ,nilssonia and it is not improbable that that genus and ,beania are closely allied types4 ,we have no definite information with regard to the reproductive organs of the ,nilssoniales3 the closer resemblance which their fronds bear in the structure of the epidermal cells to those of recent ,cycads is consistent with the view that their fertile shoots were also more like those of existing types4 ,it is1 however1 still an unsettled point whether ,beania is more closely allied to the ,cycadophyta or to the ,ginkgoales1 but the balance of opinion is in favour of the former alliance4 ,zamiostrobus4 ,endlicher4 ,cycadeostrobus4 ,carruthers4 ,though instituted by ,endlicher#adja for a cone figured by ,lindley and ,hutton as ,zamia macrocephala#adjb which is almost certainly ,abietineous and has no claim to be included in the ,cycadales1 the genus ,zamiostrobus has been adopted by many authors for ,cycadean ovulate cones1 not only such as are believed to be closely allied to those of ,zamia but for ,cycadean cones generally4 ,carruthers#adjc suggested ,cycadeostrobus as a more suitable name on the ground that it is less limited in its implication of affinity2 but1 as ,fliche points out1 ,endlicher's generic name has been widely adopted in a comprehensive sense as standing for ,cycadean megastrobili1 excluding the supposed ,cycas-like megasporophylls1 included under ,cycadospadix4 ,many of the specimens described as species of ,zamiostrobus are of little or no value as records of ,cycadean plants1 e4g4 ,zamiostrobus orientalis ,heer#adjd from the ,jurassic beds of ,amurland4 ,a ,lower ,cretaceous 7,albian7 species described by ,fliche#adje as ,zamiostrobus ,loppineti1 though not entirely satisfactory1 is more likely to belong to the ,cycadales4 ,the type-specimen is an elliptical strobilus1 #ee cm4 #cb cm41 consisting of an axis bearing at right-angles numerous small1 contiguous1 peltate megasporophylls each with two small seeds on the lower surface4 ,the figures given by ,fliche are1 however1 not convincing4 ,an examination of specimens in the ,british ,museum1 from ,wealden and ,jurassic rocks1 described by ,carruthers as species of ,cycadeostrobus1 convinced me that several are undoubtedly ,araucarian cones#adjf4 ,solms-,laubach#adjg called attention to the ,araucarian appearance of ,cycadeostrobus ,brunonis1 a cone from an unknown locality1 and this with other species1 e4g4 ,c4 elegans1 ,c4 sphaericus1 ,c4 truncatus1 etc41 may safely be referred to ,araucarites4 ,the specimen figured by ,lindley and ,hutton#adjh as ,zamia crassa from the ,inferior ,oolite of ,towcester 7,northamptonshire7 affords no satisfactory evidence of ,cycadean affinity4 ,the ,lower ,cretaceous ,bohemian specimens described by ,corda#adji and ,velenovsk#adaj as ,microzamia gibba should not be included in a genus implying ,cycadean affinity3 though ,velenovsk states that the megasporophylls bear a pair of seeds his illustrations do not afford any satisfactory evidence of this ,cycadean character4 ,similarly the fossil regarded by ,carruthers#adaa as probably a male flower of ,bucklandia is almost certainly an ,araucarian cone4 ,a small cone from the ,lower ,miocene of ,armissan 7,aude7 named by ,schimper ,zamiostrobus ,saportana and figured by ,saporta and ,marion#adab may1 as ,solms-,laubach says1 be ,cycadean1 but we have no information with regard to the internal structure or as to the presence or position of the seeds4 ,androstrobus4 ,schimper4 ,schimper#adac instituted this genus for #8amenta1 cycadeacea antherifera1 cylindrica1 e squamis imbricatis1 latere postico antheras sessiles ferentibus efformata4' ,it may conveniently be applied to fossils which resemble the male cones of recent ,cycads sufficiently to justify the use of a name implying relationship4 ,as so defined1 ,androstrobus is used in a more restricted sense than the word suggests1 just as ,masculostrobus#adad has been employed for fossils that are believed to be the corresponding organs of ,conifers4 ,among the few species assigned to ,schimper's genus reference may be made to ,a4 ,balduini ,sap41 originally named by ,schimper ,a4 zamioides1 from the ,upper ,bathonian of ,etrochy1 and ,a4 ,guerangeri 7,brongn471 another ,french type#adae4 ,heer's species ,a4 sibirica#adaf of ,jurassic age is represented by a slender axis bearing numerous appendages which in surface-view have the form of polygonal discs3 there are no indications of microsporangia and the evidence of ,cycadean affinity is far from convincing4 ,nathorst's ,rhaetic species ,a4 borealis#adag is no more satisfactory as a record of a ,cycadean strobilus4 ,a fossil from the ,lower ,cretaceous of ,bohemia described as ,zamites familiaris and regarded by ,corda#adah and ,carruthers#adai as a male flower of a ,cycad though not above suspicion may be included in ,androstrobus4 ,under the name ,friia nobilis ,velenovsk#adbj described some cones from the ,lower ,cretaceous plant-beds of ,bohemia which he regards as male strobili of some ,cycadean plant3 the cone1 as shown in ,velenovsk's restoration1 is #aj cm4 long and #e cm4 in diameter2 it bears a close superficial resemblance to a large cone of ,zamia and consists of a stout axis bearing contiguous peltate1 hexagonal1 scales gradually contracted towards the proximal end1 similar to those of ,androstrobus4 ,the evidence on which this species is identified as a male cone rests on the occurrence of numerous pits on the surface of the scales2 but no spores or sporangia were found and the pits as shown in the published figures do not present the appearance of scars of sporangia4 ,the ,rhaetic specimen originally named by ,nathorst ,androstrobus ,scotti and afterwards transferred to the genus ,lycostrobus was described in ,volume ii4#adba ,androstrobus ,nathorsti ,seward4 ,the type-specimens were obtained from the ,wealden beds of ,sussex3 they were referred to the genus ,androstrobus on evidence which cannot be regarded as decisive#adbb4 ,a fairly stout axis1 #fe cm4 long1 bearing spirally disposed sub-triangular scales hexagonal in section and attached to the axis by a broad base2 the scales1 or sporophylls1 are #a-ae cm4 long and gradually tapered towards a pointed or slightly rounded apex4 ,near the proximal end of some of the sporophylls there are regularly arranged polygonal depressions which may be impressions of microsporangia4 ,the regular disposition of the depressions is a striking feature and in contrast to the less regular reticulum exposed after the removal of the sporangia from the microsporophyll of a recent ,cycad4 ,an examination of the cuticular membrane of the microsporophylls shows that the epidermal cells have thick and straight walls#adbc1 characters consistent with the supposed ,cycadean affinity of the strobilus4 ,,chapter ,,xxxix4 ,,cycadophytan ,,fronds4 ,occasional reference is made to ,cycadean fronds in the account of flowers and stems but it is seldom that genera or species founded on leaves can be definitely correlated with particular types of reproductive organs or stems4 ,as in the case of ,ferns and ,pteridosperms so also with detached leaves believed to be ,cycadean1 a large number of generic names have been employed for impressions which afford no information with regard to anatomical characters except1 in some of the more favourably preserved specimens1 a few facts as to the epidermal cells4 ,though association often suggests original connexion it is inadvisable except in well established cases to extend to fronds generic terms based on reproductive shoots4 ,the designation ,zamites has long been used for fronds that are clearly not closely related to recent species of ,zamia1 and were it not an old established genus the significance of which is not likely to be misunderstood1 it would be wiser to substitute for it some name implying no affinity with any existing type4 ,on the other hand the employment by some authors of such generic names as ,encephalartos and ,ceratozamia is not warranted by the evidence furnished by the imperfect material4 ,prof4 ,newberry#adbd described as ,encephalartos8 denticulatus a piece of a frond from ,rhaetic beds in ,honduras characterised by lanceolate pinnae 7#cj #f mm47 gradually narrowed towards the acute apex and abruptly contracted at the base3 the method of attachment of the pinnae appears to agree with that in the genus ,zamites4 ,in this case there is no valid reason for assuming a relationship with ,encephalartos or with any recent type4 ,an impression from ,lower ,cretaceous1 ,dakota1 beds in ,kansas described as ,encephalartos cretaceus ,knowlt4 ex ,lesq4 ms4#adbe consists of a piece of lamina1 #i #d cm41 obovate-oblong and with a cuneate base1 a serrate margin and thick diverging veins3 the specimen is too incomplete to serve as a record of any ,cycadean genus4 ,the generic name ,encephalartopsis was applied by ,fontaine#adbf to some imperfect pinnae from the ,potomac beds characterised by a linear-elliptical lamina with a spinous margin and slightly diverging and occasionally anastomosing veins4 ,the figured examples of the type-species1 ,e4 nervosa1 suggest pinnae like those of ,ctenis2 but in the absence of a rachis the method of attachment of the segments cannot be ascertained4 ,saporta#adbg named a specimen from the ,miocene flora of ,koumi1 ,greece1 ,encephalartos ,gorceixianus because of its resemblance in habit to some species of the recent genus2 but the designation ,zamites would be more appropriate4 ,ettingshausen recorded an imperfect impression of a pinna from ,tertiary rocks in ,styria as ,ceratozamia ,hofmanni#adbh although it is by no means certain that the fragment is even ,cycadean4 ,the genus ,taeniopteris was described in the second volume of this book as probably a ,pteridophyte1 though of uncertain systematic position3 it has1 however1 been shown by ,mr ,thomas#adbi that the ,jurassic species ,t4 vittata was almost certainly borne on a stem with reproductive organs constructed on the ,bennettitalean plan4 ,further research may enable us to fix the position of other species but as yet ,t4 vittata is the only representative of the genus which there is good reason for assigning to the ,bennettitales4 ,it is undoubtedly true that ,cycadean plants1 using the term in a wide sense to include the ,bennettitales as well as the ,cycadales1 bulked largely in ,upper ,triassic1 ,rhaetic1 ,jurassic-,wealden floras2 the ,bennettitales probably reached their maximum development as regards wealth of form and geographical range in the latter part of the ,jurassic period and in the earliest phase of the ,cretaceous epoch4 ,in ,triassic floras ,cycadean plants are represented almost solely by fronds but the very close resemblance between ,keuper species and forms that in ,jurassic rocks are found in association with fertile shoots leaves little doubt as to the affinity of ,keuper and ,rhaetic species4 ,the evidence obtained from ,permo-,carboniferous strata is much more meagre1 at least as regards ,cycadean leaves3 the occurrence of certain morphological ,cycadean features is revealed by petrified vegetative organs of ,palaeozoic plants1 and the ,cycadean plan of organisation is conspicuous in many ,carboniferous and ,permian seeds4 ,the discovery of frond-impressions identical in external characters with ,mesozoic genera may be accepted as a substantial indication that genera already existed possessing foliage of the ,cycadean type1 though we have no certain information with regard to the nature of the other organs of the parent-plants4 ,a few examples of ,palaeozoic species are included among those selected in illustration of the different genera1 namely ,plagiozamites ,planchardi1 ,sphenozamites ,rochei1 ,pterophyllum ,fayoli1 ,p4 ,cambryi3 among other recorded instances of ,palaeozoic species are ,pterophyllum ,cottaeanum ,gutb4#adcj1 a ,permian type similar in habit to ,ctenis but without anastomosing veins1 a feature in which it resembles ,pseudoctenis2 the ,carboniferous species ,pterophyllum inflexum ,eich4#adca from the ,altai mountains1 transferred by ,zeiller to ,dioonites2 ,p4 blechnoides ,sand4#adcb from the ,stephanian of ,oppenau2 ,pterophyllum ,grand',euryanum#adcc from ,upper ,carboniferous beds in ,france1 and ,p4 gonorrachis ,goepp4#adcd from ,silesia4 ,an examination of the type-specimens of the ,carboniferous species ,cycadites gyrosus ,goepp4 and ,c4 taxodinus ,goepp4#adce in the ,breslau ,museum led me to regard the material as too imperfect to determine4 ,a conclusion that is forced upon us by a consideration of the geological range of ,cycadean fronds is that at the close of the ,wealden period1 a period very closely linked in the character of the vegetation with the preceding ,jurassic floras1 there appears to have been a relatively sudden decrease in the number of members of the ,cycadophyta3 the decline in the fortunes of ,cycadean plants is coincident with the rise and remarkably rapid extension of the ,angiosperms4 ,from ,middle and ,upper ,cretaceous and from ,tertiary beds very few ,cycadean remains have been obtained and many of them are represented by fragmentary fossils that afford no definite evidence of affinity to recent genera4 ,the antiquity of the ,cycadales1 that is the section represented by existing ,cycads1 cannot be determined2 but it would seem probable that if the ,cycads apart from the ,bennettitales existed in ,jurassic and ,lower ,cretaceous floras they occupied a very subordinate position in comparison with the extinct ,bennettitales4 ,there are no data pointing to any widespread occurrence of the ,cycadales in the ,northern ,hemisphere in ,tertiary times at all comparable with the geographical range of ,tertiary ancestors of the solitary survivor of the ,ginkgoales4 ,the following records of ,tertiary ,cycadean fronds illustrate the paucity of the records4 ,reference has already been made to ,encephalartos ,gorceixianus ,sap4 of ,miocene age1 a species that has no claim to be regarded as an example of the recent ,south ,african genus4 ,the specimen described by ,saporta and ,marion as 8 ,zamites palaeocenicus#adcf from the ,eocene of ,gelinden is too imperfect to serve as a trustworthy record4 ,a more satisfactory species1 similar in habit to ,zamites gigas1 is that on which ,saporta founded the species ,zamites epibius#adcg from ,lower ,miocene beds at ,bonnieux 7,vaucluse71 ,france4 ,another ,tertiary species is mentioned by ,krasser#adch from ,pliocene strata in ,brazil as ,zamia praecedens ,krass4 ex ,ett4 ,,ms4 ,ettingshausen has described a ,tertiary species from ,new ,south ,wales1 either ,lower ,miocene or ,upper ,eocene in age1 as ,anomozamites ,muelleri#adci1 characterised by truncate segments with simple veins and set obliquely to the rachis4 ,while certain form-genera of fronds can only be referred to the ,cycadophyta1 in other cases it is possible to assign fronds to a section of this comprehensive group characterised by a particular type of fertile shoot and by certain well defined epidermal features4 ,the investigation of the cuticular structure of various ,cycadean fronds by ,nathorst#addj and especially by ,mr ,thomas#adda has supplied a basis of classification which affords the best criterion of affinity so far available4 ,the majority of fronds are placed in the ,bennettitales while the three genera ,ctenis1 ,nilssonia1 and ,ctenopteris 7or ,ptilozamites#addb7 are placed in the ,nilssoniales4 ,i4 ,bennettitales4 ,epidermal cells characterised by sinuous walls and generally rectangular2 the cuticle is thin2 the stomata1 confined to the lower surface of the pinnae1 tend to be arranged at right-angles to the veins and are on a level with the epidermis or very slightly depressed2 two large laterally placed subsidiary cells more or less surround the guard-cells and these are provided with thickenings of a definite shape 7figs4 #eid1 #fji74 ,genera3 ,ptilophyllum1 ,zamites1 ,otozamites1 ,dictyozamites1 ,pterophyllum and ,anomozamites1 ,taeniopteris1 ,pseudocycas4 ,,ii4 ,nilssoniales4 ,epidermal cells with straight walls1 not sinuous1 irregular in form1 rounded1 hexagonal1 or rectangular2 the stomata are below the level of the epidermis2 the cuticle may be thin or thick4 ,there is no regular arrangement of the stomata2 the guard-cells are surrounded by #f-h subsidiary cells 7fig4 #fbe7 which often form an overarching canopy2 thickening lamellae like those on the guard-cells of the ,bennettitales are seldom present4 ,genera3 ,nilssonia1 ,ctenis1 ,ctenopteris4 ,it is a noteworthy fact that the representatives of the smaller group1 the ,nilssoniales1 in their cuticular features1 are more akin than the ,bennettitales to modern ,cycads4 ,until definite evidence is obtained as to the nature of the reproductive organs of ,nilssonia1 ,ctenis1 and ,ctenopteris it is impossible to say how closely these genera agree in essential characters with existing members of the ,cycadales4 ,if1 as has been suggested1 the fertile shoots known as ,beania#addd belong to ,nilssonia their resemblance in plan of construction to the cones of recent genera1 much greater than in the case of the flowers of the ,bennettitales1 is in accordance with the evidence of the epidermal characters4 ,reference was made in the second ,volume of this book to several genera founded on fronds which through lack of evidence as to the nature of the reproductive organs cannot be assigned with certainty either to ,ferns or ,cycads3 it was stated that the genera ,ptilozamites and ,ctenopteris are probably ,cycadean1 and the structure of the epidermal cells in the latter genus lends support to this view#adde4 ,among other genera of doubtful position not included in the following descriptions of fronds is ,zamiopsis of ,fontaine#addf founded on large compound fronds from the ,potomac formation3 the venation and form of the pinnae are more ,fern-like than in ,ctenopteris1 but in general habit the two genera are not very dissimilar4 ,the generic name ,zamiopsis is misleading as the species bear no resemblance to ,zamia or ,zamites4 ,i4 ,bennettitales4 ,,ptilophyllum4 ,morris4 ,the generic name ,ptilophyllum was instituted in #ahdj for some specimens of pinnate fronds from ,cutch3 in this genus ,morris#addg included with the ,indian leaves the ,english ,jurassic species ,pterophyllum pecten ,lind4 and ,hutt4#addh 7figs4 #ehg1 etc47 and some other forms4 ,he defined ,ptilophyllum as follows3 #8,fronds pinnate2 pinnae closely approximated1 linear1 lanceolate1 more or less elongate1 imbricate at the base1 attached obliquely2 base semicircular or rounded2 veins equal1 slender1 parallel4' ,morris adds that he instituted a new genus in preference to ,zamites because of the #8oblique insertion of the pinnae and their overlapping each other at the base4' ,in a later paper ,morris#addi states that the pinnae of ,ptilophyllum fronds are #8sometimes auriculed in the upper and sometimes in the lower part' of the base of the lamina4 ,in his catalogue#adej he adopted ,endlicher's genus ,palaeozamia instead of ,ptilophyllum4 ,without discussing the generic nomenclature adopted by various authors for the ,indian types and similar fronds it is important to refer briefly to the treatment of ,morris's species by ,oldham and ,morris and by ,feistmantel4 ,in the first of the series of ,memoirs on ,gondwana floras#adea ,ptilophyllum is retained for a section of ,palaeozamia together with ,otozamites and ,sphenozamites as other sectional subdivisions3 in the subgenus ,ptilophyllum are included ,palaeozamia acutifolia and ,p4 cutchensis 7fig4 #ehh1 ,a1 ,c71 also ,p4 affinis1 ,p4 rigida1 and ,p4 bengalensis4 ,the last species is in all probability an ,otozamites3 ,p4 affinis and ,p4 rigida are almost certainly indistinguishable from ,p4 cutchensis4 ,feistmantel#adeb dealt in detail with the genus ,ptilophyllum3 he wrote1 #8with ,schimper and ,schenk ,i therefore look upon this genus as an ,indian type especially characterised by its 444 more or less slender leaves1 angustate towards the apex and base1 and petiolate1 with regularly adfixed leaflets4444 ,the leaflets are equal to each other1 for the most part elongate linear1 and auriculate and free at the upper angle at the base1 but adfixed at the lower angle1 and each is decurrent behind the upper angle of the leaflet next below it1 thus the leaflets are almost imbricate4 ,the veins are rather numerous1 simple1 and forked1 and more or less divergent#adec4' ,feistmantel distinguishes certain varieties of ,p4 cutchense 7fig4 #ehh1 ,a1 ,c71 none of which appear to be well defined4 ,a specimen from the ,rajmahal ,hills with unusually long pinnae1 the frond having a breadth of #h cm41 is described as ,ptilophyllum acutifolium var4 maximum#aded1 but it differs in no important feature from the smaller and commoner form4 ,the next point to be considered is the variability of certain species referred by ,feistmantel to ,otozamites4 ,he figures specimens from the ,jabalpur group as ,o4 ,hislopi ,feist4 ex ,old4 ,,ms41 ,o4 gracilis 7,kurr71 ,o4 angustatus ,feist4 7fig4 #ehh1 ,b7 and ,o4 distans#adee4 ,an examination of the figured specimens leads me to regard ,o4 ,hislopi and ,o4 gracilis as identical with the ,ptilophyllum fronds3 the pinnae exhibit no distinguishing features and there is no reason for a specific1 still less a generic1 separation4 ,otozamites angustatus is indistinguishable from ,otozamites sp4 as figured from the ,madras coast and from ,ptilophyllum cutchense1 ,p4 cutchense var4 curvifolium and var4 minimum4 ,the drawings reproduced in fig4 #f;a1 ,pl4 x4 of the ,madras flora#adef and in fig4 #h;a1 ,pl4 vi4 of the ,jabalpur flora#adeg showing auriculate bases are inaccurate3 in all the fronds named the pinnae are straight with rounded edges precisely as in ,ptilophyllum4 ,the conclusion forced upon me by a comparison of the actual specimens is that the ,indian fronds are not separable into well-defined species and should all be included in ,ptilophyllum cutchense4 ,moreover in this comprehensive species should be included the specimens described by ,feistmantel as ,otozamites ,hislopi 7fig4 #ehi71 ,o4 angustatus1 and ,o4 gracilis4 ,it may well be that a more detailed investigation of the numerous forms comprised in this protean species1 particularly if specimens are obtained from which cuticular preparations can be made1 may lead to the recognition of additional species or well-defined varieties4 ,the resemblance between the various forms of ,p4 pecten from the ,jurassic strata of ,yorkshire and those of ,p4 cutchense from ,india is very striking1 and at least in many cases no specific separation is possible so far at least as the form of the fronds and pinnae is concerned4 ,the occasional close association of ,ptilophyllum fronds and ,williamsonia flowers is an important agreement between the ,english and ,indian fronds 7fig4 #eij74 ,illustration3 ,fig4 #ehg4 ,ptilophyllum pecten4 7,british ,museum1 ,v4 #cgie2 nat4 size47 ,illustration3 ,fig4 #ehh4 ,ptilophyllum pecten4 ,a1 ,c1 specimens figured by ,feistmantel as ,ptilophyllum cutchense4 ,b1 ,feistmantel's ,otozamites angustatus4 7 nat4 size2 ,calcutta ,museum47 ,illustration3 ,fig4 #ehi4 ,ptilophyllum pecten4 ,a frond figured by ,feistmantel as ,otozamites ,hislopi4 ,a1 nat4 size2 ,b1 enlarged 7,calcutta ,museum74 ,in the first part of the ,catalogue of ,jurassic plants from ,yorkshire the opinion was expressed#adeh1 based on an examination of ,morris's type-specimen of ,ptilophyllum cutchense and of a large number of ,english and other fronds identical with or closely allied to ,pterophyllum pecten ,lind4 and ,hutt41 that the ,indian and ,european fronds belong to the same genus4 ,in a later paper#adei it was maintained that ,p4 cutchense and ,p4 acutifolium are probably identical with the ,english type1 and a drawing was published--reproduced in fig4 #eia--of ,morris's type-specimen4 ,dr ,halle#adfj has discussed the genus ,ptilophyllum and his investigations lead him to a different conclusion2 he1 like ,zeiller and some other authors1 employs ,ptilophyllum in ,feistmantel's sense4 ,the pinna-base is said to agree in its asymmetrical form with that in ,otozamites1 while it differs from the symmetrical base of ,zamites pinnae4 ,in ,ptilophyllum both edges of the pinna-base are said to bend down in joining the rachis2 at the upper corner the base thus becomes rounded and for some distance free from the rachis2 it is also sometimes a little auriculate2 at the lower edge the pinna is decurrent on the upper surface of the rachis4 ,in a subsequent paper ,halle#adfa repeats the view that the decurrence of the pinnae by their lower edges is an important distinguishing feature of ,ptilophyllum1 thus agreeing with ,feistmantel whose illustrations appear to be confirmatory4 ,the drawings in ,feistmantel's memoirs are1 however1 misleading and in some cases incorrect4 ,an examination of a photograph of ,morris's type-specimen of ,p4 cutchense led ,halle to conclude that the two edges of the pinna-base bend downwards on joining the rachis as described by ,feistmantel4 ,this feature is not shown in the drawing reproduced in fig4 #eia3 it is clear that either the drawing is incorrect or that there has been some mistake in the interpretation of the photograph4 ,through the courtesy of ,dr ,halle ,i have been able to examine the actual print3 when viewed in its correct position the two edges of the pinnae appear to bend down as described by ,halle1 but if it is examined in the reverse position the lower angle of the pinnae is seen to be slightly rounded as in fig4 #eia1 the apparent decurrence being due to a confusion between the appressed lower edge of one pinna1 which is faintly shown1 and the stronger downward trend of the upper edge of the pinna next below4 ,the upper edges of the pinnae are more prominent because they are less appressed to the rachis while the lower half of the base is closer to the rachis and is frequently1 though not in ,morris's specimen1 overlapped by the upper edge of the next lower pinna4 ,a re-examination of the type-specimen in the ,british ,museum confirms this interpretation4 ,the pinnae of ,ptilophyllum are characterised by their attachment to the upper face of the rachis which they almost completely cover2 the upper angle is rounded and in a few cases auriculate 7fig4 #eib72 the lower angle of the base is slightly rounded and not infrequently hidden by the imbrication of the adjacent pinna2 it is occasionally auriculate 7fig4 #eic74 ,the pinnae are attached by nearly the whole base1 but the upper angle is free4 ,the veins are parallel1 sub-parallel or1 especially in the proximal portion of the lamina1 oblique4 ,the pinnae are linear1 varying considerably in relation of length to breadth and in the form of the apex2 they are straight or more or less falcate4 ,the epidermal cells of such ,ptilophyllum fronds as have been examined are characterised by strongly looped or sinuous walls2 the stomata1 confined to the lower surface1 are roughly circular and the guard-cells are at right-angles to the veins and not appreciably sunk4 ,fig4 #eid represents the appearance of a stoma in surface-view3 #8on either side of the central slit-like pore are two elliptical or hemispherical structures2 they are somewhat flattened when they abut on the pore1 and have rounded ends4444 ,between these and the subsidiary cells lie two other thickened patches1 more or less hemispherical in shape1 and apparently overlying the central structures4' ,on the analogy of similar appearances in recent ,cycads ,mr ,thomas#adfb interprets the two pairs of thickened patches as belonging to the upper and lower sides of the highly inclined guard-cells4 ,this author calls special attention to the abundance on some of the fronds included in the aggregate species ,p4 pecten of regular rows of circular hair-scars preserved as small annulate projections1 #jc-jd mm4 in diameter4 ,a comparison of the cuticles of different forms of ,ptilophyllum pecten enabled ,thomas to recognise more than one type3 for one of these the name ,ptilophyllum hirsutum is proposed4 ,it is by such work as this that we may hope to discover differentiating characters4 ,illustration3 ,fig4 #eij4 ,ptilophyllum pecten 7,p4 cutchense7 and ,williamsonia ,blanfordi4 ,drawn from a specimen figured by ,feistmantel 7#gf7 ,pl4 xii4 fig4 #f4 ,illustration3 ,fig4 #eia4 ,part of the type-specimen of ,ptilophyllum cutchense ,morris4 7,british ,museum2 #c47 ,illustration3 ,fig4 #eib4 ,ptilophyllum pecten4 7,manchester ,museum1 ,williamson ,coll4 #cgbf47 ,illustration3 ,fig4 #eic4 ,ptilophyllum pecten4 ,from the ,lower ,estuarine beds1 ,cleveland1 ,yorkshire4 7,after ,thomas2 nat4 size47 ,illustration3 ,fig4 #eid4 ,ptilophyllum pecten2 stoma4 7,after ,thomas and ,bancroft47 ,the different forms of ,williamsonia flowers found in association with fronds of the ,ptilophyllum habit also point to the inclusion of more than a single species under the group-species ,p4 pecten4 ,as additional evidence is obtained further analysis will be possible1 but in dealing with impressions which include specimens transitional from one form of frond to another1 the most convenient and to my mind the most logical course is to treat a species as an aggregate- or group-species4 ,some authors believe that the two fronds described by ,phillips as ,cycadites pecten and ,c4 pectinoides are distinct species#adfc1 but there would seem to be no adequate reason for this view4 ,the fronds described by ,heer#adfd from the ,lower ,cretaceous of ,greenland as species of ,zamites and similar leaves from ,graham ,land included in that genus by ,halle#adfe are in my opinion inseparable from ,ptilophyllum1 and this applies equally to ,otozamites ,hislopi 7,old47 7fig4 #ehi7 and ,o4 abbreviatus as figured by ,feistmantel and by ,halle4 ,the nomenclature of ,cycadean fronds having the habit of ,ptilophyllum pecten is a great difficulty3 after carefully reconsidering the whole question and comparing ,feistmantel's figured specimens with the large series of ,english fronds the conclusion reached is that the characters exhibited by ordinary impressions do not admit of any satisfactory grouping under well-defined specific types4 ,in the first place1 as already indicated1 the use by some authors of the generic names ,ptilophyllum1 ,otozamites1 and ,zamites creates a false impression of the degree of difference between the numerous forms of frond agreeing more or less closely with the specimens on which were founded the species ,ptilophyllum acutifolium1 ,p4 cutchense1 ,p4 pecten1 and ,p4 pectinoides 7figs4 #ehg1 #eia1 #eie1 etc474 ,in his important memoir on the ,jurassic flora of ,graham ,land ,halle#adff discusses the limitation of ,ptilophyllum1 ,zamites1 and ,otozamites4 ,he employs ,zamites for fronds with linear pinnae attached to the upper face of the rachis by a base which is more or less1 but often very little1 rounded and always asymmetrical1 with or without a basal callosity3 fronds of the type ,z4 gigas he includes in the section ,euzamites1 while ,z4 borealis and similar forms 7fig4 #eig7 are referred to a second section1 ,subzamites4 ,it is in the sense of ,halle's section ,euzamites that the generic name ,zamites is employed in this chapter4 ,on the other hand the fronds grouped by ,halle as ,subzamites have pinnae with the basal angles of the lamina very slightly rounded precisely as in ,ptilophyllum as seen in fig4 #eif 7cf4 fig4 #eih which represents fronds referred by ,halle to ,zamites72 and they are not distinguished by any feature of generic importance from ,ptilophyllum as defined on page #eai4 ,the species ,zamites pusillus1 ,z4 ,anderssoni1 and ,z4 antarcticus 7fig4 #eih7 described by ,halle from ,graham ,land as well as ,heer's ,arctic forms#adfg ,z4 borealis 7fig4 #eig71 ,z4 speciosus1 ,z4 brevipennis1 and others are transferred to ,ptilophyllum as types agreeing very closely with ,p4 pecten and in some cases not clearly distinguishable from it even specifically4 ,otozamites is the name employed by ,halle for fronds with pinnae having contracted1 asymmetrical and auriculate1 bases1 the anterior lobe being more developed than the posterior4 ,the asymmetry of the pinna-base is considered an essential feature4 ,as ,halle states it is very difficult in some instances to draw a distinction between ,otozamites and ,ptilophyllum4 ,as used in this chapter ,otozamites signifies fronds with pinnae characterised by an auriculate base1 a lamina usually broader than in ,ptilophyllum1 and by more spreading veins 7fig4 #fjd74 ,the not infrequent occurrence of auriculate pinnae on fronds 7fig4 #fjc1 ,a7 which cannot be separated from typical examples of ,p4 pecten illustrates the narrow dividing line as regards the form of the pinna-base between ,ptilophyllum and ,otozamites4 ,the ,indian species ,o4 ,hislopi 7fig4 #ehi7 and ,o4 abbreviatus1 to which ,halle refers some ,antarctic fronds1 cannot be distinguished from the ,english ,p4 pecten or ,feistmantel's and ,morris's ,indian fronds described as ,p4 cutchense and ,p4 acutifolium3 these forms are therefore included in ,ptilophyllum4 ,ptilophyllum 7,williamsonia7 pecten 7,phillips74 ,this designation is employed in a wide sense for a group of fronds exhibiting a considerable range in size1 in the relative breadth and length of the linear pinnae1 and in other features4 ,under ,p4 pecten are included 7i7 the ,english fronds from ,yorkshire first described by ,phillips#adfh as ,cycadites pecten and ,c4 pectinoides1 the former from the ,middle shale1 the latter from the ,lower shale of the ,yorkshire coast1 together with the ,stonesfield slate specimens named by ,sternberg#adfi ,polypodiolites pectiniformis 7fig4 #eie7 and by ,brongniart#adgj and ,lindley and ,hutton#adga ,zamia pectinata2 7ii7 the ,indian specimens already considered and 7iii7 numerous examples recorded under different names from ,jurassic strata in many countries4 ,fronds from the ,yorkshire coast named by ,brongniart#adgb ,zamia ,goldiei1 though regarded by some authors as examples of ,otozamites1 are probably referable to ,p4 pecten4 ,andrae's ,pterophyllum rigidum#adgc 7fig4 #eif7 from ,steierdorf is almost certainly a form of ,ptilophyllum pecten4 ,the specimen shown in fig4 #ehg is one of the few examples of fronds apparently preserved in their original position attached in a cluster to a ,williamsonia 7,bucklandia7 type of stem4 ,the range in size and form of the pinnae is illustrated in figs4 #ehh1 #eib1 #eic4 ,illustration3 ,fig4 #eie4 ,ptilophyllum pecten4 ,the specimen figured by ,sternberg as ,polypodiolites pectiniformis4 7,oxford ,museum2 nat4 size47 ,illustration3 ,fig4 #eif4 ,ptilophyllum pecten4 ,andrae's ,pterophyllum rigidum from ,steierdorf1 ,banat4 7,british ,museum1 ,no4 #dadch2 nat4 size47 ,fronds linear1 tapering gradually towards the base and apex1 often characterised by a marked uniformity in breadth4 ,the pinnae1 short or comparatively broad or long and narrow1 are straight or more or less falcate2 the apex is obtuse or acute or the upper margin of the lamina may be almost straight and the lower edge curved abruptly upwards at the apex2 the pinnae are usually attached obliquely to the rachis but may be almost at right-angles2 with the exception of the upper angle1 the whole of the base is attached to the frond-axis2 the base of the lamina may be symmetrical1 both angles being slightly rounded1 or asymmetrical1 the upper or less frequently the lower corner being auriculate 7figs4 #eib1 #eic74 ,there is no basal callosity on the lamina nor is there a median sinus4 ,the veins are more or less spreading at the base but for the most part parallel4 ,the features of the epidermal cells and stomata are mentioned in the general account of the genus4 ,fertile shoots of plants with this type of frond are described under ,williamsonia4 ,very little is known of the stems which bore ,ptilophyllum fronds1 but as stated on page #dhh ,indian specimens show leaves of ,ptilophyllum cutchense attached to a piece of stem 7fig4 #egi7 having the characters of ,bucklandia and characterised by a xylem-cylinder denser than in recent ,cycads2 the structure of the wood at least in the ,indian stem is rather pycnoxylic than manoxylic4 ,the fronds grouped under ,ptilophyllum pecten are very widely distributed in ,jurassic floras2 they are recorded from many localities in ,europe1 from ,turkestan#adgd1 ,india1 ,graham ,land#adge1 ,patagonia#adgf1 and elsewhere4 ,as thus defined this #8species1' or more correctly this group of forms1 undoubtedly includes more than one species in the strict sense1 but without additional data it is maintained that the recognition of clearly defined specific types or varieties is beyond our power4 ,it may be urged that in view of the wide geographical range of the ,ptilophyllum pecten type of frond and the admitted probability that several species in the narrower sense are represented1 distinctive specific names should be retained even though under such designations are included forms that1 so far as can be seen from impressions1 exhibit no constant distinguishing features4 ,my purpose is to emphasise the futility of attempting to found well-marked species on the available material4 ,the student must decide for himself what course to pursue1 whether to retain such a specific name as cutchense for the ,indian fronds or to employ that and other specific names as designations of geographical types differing in no clearly defined or constant characters from examples of the ,english ,ptilophyllum pecten4 ,a comparative examination of the cuticular membranes in the comparatively few cases where that is possible would probably furnish a basis for a satisfactory subdivision of the group-species4 ,the names ,ptilophyllum ,anderssoni1 ,p4 boreale1 and ,p4 antarcticum are retained for certain forms selected from a number of closely allied types partly on the ground that these fronds exhibit some more or less well-marked distinctive characters and in part as a recognition of the existence of geographical forms4 ,ptilophyllum boreale 7,heer74 ,heer#adgg described numerous well-preserved impressions of pinnate fronds from the ,lower ,cretaceous plant-beds of ,kome1 ,greenland1 which he referred to several species of ,zamites though the differences between them are hardly of specific rank4 ,an inspection of several of the figured specimens in the ,stockholm ,museum showed that ,heer's drawings are in the main accurate4 ,zamites borealis 7fig4 #eig7 is characterised by small linear pinnae attached to the upper face of the rachis1 the stoutness of which is a noteworthy feature2 the veins are parallel and simple4 ,in the shape of the pinnae1 including the base-characters1 this species agrees closely with ,p4 pecten4 ,the slightly falcate or straight pinnae are #ag-b mm4 broad and reach a length of #ae mm42 in ,z4 speciosum ,heer1 probably specifically identical with ,p4 boreale1 the pinnae are relatively longer1 and in ,z4 brevipennis ,heer they resemble the shorter pinnae of some of the narrow fronds of ,p4 pecten4 ,a preparation of the cuticle of a pinna of ,p4 boreale made by ,mr ,thomas from a specimen in the ,stockholm ,museum shows a marked difference between the upper and lower epidermis3 the cells on the upper surface of the lamina have very thick and sinuous walls precisely as in ,p4 pecten1 but the cells are often broader than long and not elongated parallel to the long axis of the pinna2 those of the lower epidermis are thinner and less clearly preserved3 the stomata1 which appear to be like those of ,p4 pecten1 are scattered and not in rows4 ,illustration3 ,fig4 #eig4 ,ptilophyllum boreale 7,heer74 ,drawn from one of the specimens from the ,lower ,cretaceous beds at ,ekkorfat1 ,greenland1 figured by ,heer4 7,stockholm ,museum2 nat4 size and a few pinnae enlarged47 ,ptilophyllum antarcticum 7,halle74 ,the fronds from the ,jurassic rocks of ,graham ,land1 described by ,halle as ,zamites antarcticus#adgh1 are very similar to some forms of ,p4 pecten and to ,p4 boreale and other ,greenland forms2 the linear subacute pinnae are attached to the upper face of the rachis at a wide angle and the base of the lamina is truncate and may be very slightly constricted4 ,the veins are dense1 as many as #e in #a mm41 and they are occasionally forked near the base 7fig4 #eih1 ,a74 ,illustration3 ,fig4 #eih4 ,a1 ,a1 ,ptilophyllum antarcticum4 ,b1 ,p4 ,anderssoni4 7,after ,halle47 ,ptilophyllum ,anderssoni 7,halle74 ,this ,graham ,land species 7fig4 #eih1 ,b71 referred by ,halle to ,zamites#adgi1 is of the same general type as ,p4 pecten1 but is characterised by a coarser venation and by the wider angle of attachment of the pinnae4 ,ptilophyllum ,dunkerianum 7,goeppert74 ,goeppert#adhj proposed the name ,pterophyllum ,dunkerianum for some specimens from the ,wealden of ,north ,germany which were afterwards figured by ,dunker#adha4 ,miquel#adhb included the species in his genus ,dioonites and this name has been adopted by other authors4 ,attention has been drawn to the inconsistent use of the title ,dioonites#adhc1 and ,i have previously employed the name in a sense similar to that in which it has been adopted by ,nathorst1 that is for fronds with long and narrow pinnae without any basal constriction and not auriculate1 attached more or less at right-angles to the upper face of the rachis2 but so defined ,dioonites differs in no essential particular from forms of ,ptilophyllum or from fronds referred by authors to ,schimper's genus ,ctenophyllum4 ,the name ,ctenophyllum#adhd was instituted for certain fronds differing in some points from ,otozamites and ,dioonites4 ,one such type is ,ctenophyllum 7,ptilophyllum7 pecten 7,lind4 and ,hutt473 this is quoted in ,zittel's ,handbuch as a typical representative of the genus4 ,schimper followed ,feistmantel in his definition of ,ptilophyllum1 a definition which is not in accordance with the characters of the fronds on which it was founded by ,morris4 ,fontaine1 on the other hand1 has applied ,ctenophyllum to fronds of a different type which are now included in the genus ,pseudoctenis4 ,there would seem to be no adequate ground for the retention of ,ctenophyllum as a generic designation4 ,the ,wealden species ,p4 ,dunkerianum is characterised by the following features3 rachis fairly stout1 pinnae approximate1 linear #b-c mm4 broad and reaching a length of #aa cm4 or more1 gradually narrowed towards the apex1 attached in two almost contiguous rows to the upper face of the frond-axis3 the lower margin of the lamina may be slightly decurrent1 e4g4 in the apical part of the frond or very slightly broadened and bluntly rounded4 ,the pinnae are attached at right-angles or1 near the apex1 obliquely2 veins #e-f1 parallel4 ,the epidermal cells as figured by ,schenk#adhe have very sinuous walls and are identical with those of the ,english and ,indian forms of the group-species ,p4 pecten2 the stomata are confined to the lower surface4 ,if ,schenk's drawings of the stomata are correct they differ from those of other species of the genus in their simpler structure2 there are no subsidiary cells and the guard-cells show no cuticularised bands4 ,in habit this species resembles ,encephalartos ,ghellinckii ,lehm4 7fig4 #chb74 ,the superficial resemblance of the narrow linear pinnae to those of ,cycadites led ,dunker and ,schenk to refer to that genus some specimens which have since been described as identical with ,p4 ,dunkerianum4 ,,zamites4 ,brongniart4 ,in the first instance the generic name ,zamites was used in addition to ,zamia for certain pinnate fronds including species#adhf1 such as ,z4 ,bechei1 which are now regarded as typical examples of ,otozamites4 ,subsequently ,brongniart gave up ,zamia for fossil fronds and applied ,zamites to fronds with entire pinnae1 not truncate at the apex and not decurrent but slightly constricted at the base4 ,braun's two genera ,podozamites and ,pterozamites were relegated to the position of subgenera4 ,the name ,podozamites has been employed by ,schenk#adhg for specimens now included in ,zamites1 and ,zamites is used by him#adhh for some fossils which are examples of ,podozamites as generally understood4 ,goeppert's definition#adhi of ,zamites includes fronds with pinnae of the ,otozamites type1 and this author pertinently compares ,zamites with recent ,encephalartos leaves4 ,pomel#adij proposed the name ,crossozamia for certain fronds of the ,zamites type1 but this genus with several others instituted by the same author has not been adopted4 ,bornemann#adia described ,zamites as comprising species with a greater or less resemblance to the fronds of recent ,zamias4 ,as defined below1 ,zamites fronds may be compared with those of some species of ,encephalartos1 ,ceratozamia1 and ,macrozamia4 ,there has been considerable difference of opinion with regard to the range of form in the pinnae that it is advisable to include in ,zamites4 ,the name ,zamiophyllum was proposed by ,nathorst#adib for a ,wealden species1 described by ,ettingshausen as ,pterophyllum ,buchianum 7fig4 #fja1 ,a-,c71 characterised by a decrease in the breadth of the linear pinnae towards the point of attachment and1 according to ,nathorst's description1 by the lateral attachment of the pinnae4 ,an examination of specimens of this type from ,english rocks#adic enabled me to show that the pinnae are attached to the upper face of the rachis4 ,zeiller#adid has also included ,zamiophyllum in ,zamites1 but ,halle's recent definition#adie of the latter genus excludes fronds of the ,zamiophyllum type4 ,schimper instituted the name ,glossozamites#adif for fronds bearing pinnae with rounded and slightly contracted bases and borne on grooves on the upper surface of the rachis 7fig4 #fja1 ,f74 ,in venation the pinnae agree with those of ,otozamites but the base is not auriculate4 ,kurr's ,liassic species ,pterophyllum oblongifolium#adig included by ,schimper in ,glossozamites is probably an ,otozamites4 ,another species referred to this genus is ,schenk's ,podozamites ,zitteli#adih from the ,urgonian of ,austria 7fig4 #fja1 ,f73 in this species the slightly falcate pinnae with obtuse apices have rounded and not auriculate bases and there is some evidence of a basal callosity4 ,this species agrees so closely with such a typical ,zamites as ,z4 gigas that it is difficult to see on what grounds the retention of ,glossozamites is desirable4 ,a ,portuguese specimen referred by ,saporta#adii to ,glossozamites1 ,g4 brevis1 is founded on a single specimen very like a leaflet of ,otozamites ,klipsteinii 7,dunk472 and ,g4 parvifolia ,yok4#aejj from ,china has no claim to be included among ,cycadean fronds4 ,feistmantel's ,glossozamites ,stoliczkanus#aeja is almost certainly a leaf of ,cordaites4 ,for certain fronds originally described as ,zamites ,zeiller#aejb has instituted the genus ,plagiozamites4 ,an important question as to the type of frond which may conveniently be included in the genus ,zamites was raised by the application of this name by ,heer to some ,lower ,cretaceous fronds from ,greenland1 ,z4 borealis 7 ,ptilophyllum boreale1 fig4 #eig71 and others which differ in the form of the pinnae from species usually regarded as typical of the genus4 ,halle#aejc accepts the ,greenland species as examples of ,zamites though he distinguishes them by a sectional name ,sub-,zamites2 he defines ,zamites as including fronds with pinnae attached to the upper face of the rachis with a contracted and always symmetrical base though in some cases the basal contraction is exceedingly small2 there is a more or less distinct basal callosity4 ,he recognises two types1 7i7 ,eu-,zamites1 e4g4 ,zamites gigas 7fig4 #eii71 in which the pinnae are strongly contracted basally and have a callosity1 and 7ii7 ,sub-,zamites1 e4g4 ,z4 borealis#aejd1 etc41 in which the pinnae are not so broadly rounded at the base and retain the same breadth to the point of insertion where they are #8very rapidly and very little contracted1' with or without a basal callosity4 ,the basal callosity in these forms is not shown in many of the pinnae and is at most but a slight rounding of the angles of the truncate base4 ,the specimens referred by ,halle to ,sub-,zamites do not appear to differ in any feature worthy of generic rank from ,ptilophyllum4 ,in the following definition ,zamites is employed in a sense more or less in accordance with ,brongniart's usage but with the inclusion of such forms as ,z4 ,buchianus1 the type of ,nathorst's ,zamiophyllum1 and the exclusion of ,heer's ,arctic and ,halle's ,antarctic fronds referred by them to ,zamites4 ,fronds broadly lanceolate reaching a length of over #fj cm42 pinnae more or less oblique or at right-angles to the rachis 7fig4 #eii71 attached to the upper surface but not completely covering it1 linear or linear-lanceolate1 acuminate or obtuse1 usually abruptly contracted at the rounded base and more rarely 7e4g4 ,z4 ,buchianus1 fig4 #fja7 gradually tapering to the proximal end1 with or without a callosity at the symmetrical base2 veins divergent at the base1 simple or dichotomously branched1 for the most part parallel to the edges of the lamina and slightly divergent in the apical region4 ,the presence of a basal callosity1 such as is best seen in the pinnae of recent species of ,macrozamia1 is not a feature of great importance and cannot be easily recognised in many impressions4 ,in the process of fossilisation the pinnae are often flattened against the surface of the rachis and this may produce transverse wrinklings of the lamina suggestive of a basal thickening4 ,in some cases stems of the ,bucklandia type occur in connexion with ,zamites fronds 7fig4 #eda74 ,an account of these stems1 and of inflorescences of ,williamsonia which were borne by some at least of the plants with ,zamites leaves is given in ,chapter xxviii4 ,in such examples of ,zamites as have been examined the epidermal cells have sinuous walls and the stomata#aeje1 confined to the lower face of the lamina1 occur in rows with their long axis at right-angles to that of the pinnae4 ,zamites ranges from ,rhaetic to ,lower ,cretaceous strata4 ,zamites truncatus ,zeiller4 ,a ,rhaetic species from ,tonkin#aejf characterised by oval linear pinnae given off at a wide angle1 alternate and not contiguous2 apex obtusely truncate1 gradually narrowed to a cuneate base which is rounded or elliptical and has a more or less definite callosity4 ,the pinnae vary from #c to #e cm4 in length and from #e to #ac mm4 in breadth4 ,zamites gigas 7,lindley and ,hutton74 ,the specific name gigas is retained in preference to that of ,mantelli employed by ,brongniart#aejg on the ground that he afterwards discarded it in favour of the designation proposed by ,lindley and ,hutton#aejh1 and because their name has been generally adopted4 ,fronds large1 exceeding #fj cm42 broadly linear lanceolate2 the comparatively slender rachis bears alternate linear lanceolate pinnae with a rounded and usually slightly swollen base and an acuminate apex4 ,at the apex of the frond the pinnae are narrow and linear 7fig4 #eii7 and almost parallel to the rachis2 in the lower part they are shorter and relatively broader and attached approximately at right-angles4 ,the numerous veins diverge from the centre of the base but for the most part are parallel to the edge of the lamina4 ,the form of the epidermal cells and the structure of the stomata have recently been described by ,mr ,thomas4 ,the external features of the stem 7fig4 #eda7 are described under the genus ,williamsonia4 ,in the case of fronds of this type from ,english ,jurassic rocks it would be legitimate to speak of them as ,williamsonia gigas1 but in view of the fact that such fronds usually occur as detached specimens and without any associated flowers it is advisable1 as ,nathorst maintains1 to retain the non-committal genus ,zamites4 ,illustration3 ,fig4 #eii4 ,zamites gigas4 7,british ,museum1 ,v4 #bgbc;a2 nat4 size47 ,this type of frond is widely distributed in ,jurassic strata4 ,the occurrence of many forms agreeing generally with the type-specimen but differing from it in features that are not constant or of real morphological importance renders accurate specific delimitation very difficult4 ,species that appear to be indistinguishable from ,zamites gigas by any well-marked characters are1 ,zamites ,feneonis#aeji ,brongn41 ,z4 ,moreaui#aeaj ,brongn41 ,z4 ,renevieri#aeaa ,heer1 and ,z4 claravallensis#aeab ,sap42 similarly ,z4 ,schmiedelii ,and4#aeac is probably identical with ,z4 gigas4 ,the ,lower ,cretaceous species ,zamites bohemicus#aead ,vel4 and ,z4 iburgensis#aeae ,hos4 and von d4 ,marck represent very similar forms4 ,zamites recta 7,tate74 ,illustration3 ,fig4 #fjj4 ,zamites recta4 7,uitenhage series1 ,s4 ,africa47 ,this species was originally described by ,tate#aeaf as ,palaeozamia 7,otozamites7 recta from ,wealden strata in ,south ,africa and subsequently transferred to ,zamites#aeag2 it bears a very close resemblance to ,z4 gigas4 ,the fronds bear alternate linear pinnae attached to the upper face of the rachis by a slightly contracted and swollen base4 ,the lamina has an acuminate asymmetrical apex and the upper edge is slightly falcate2 the larger pinnae are over #f cm4 long and nearly #a cm4 broad2 the veins are frequently forked as they converge towards the base of the lamina4 ,no clear evidence of association of these fronds in the ,uitenhage series of ,south ,africa with ,williamsonia flowers has been discovered1 but a specimen#aeah in the ,tate collection in the ,british ,museum may be a badly preserved cluster of bracts belonging to a ,williamsonia4 ,the rachis of this species shows some peculiar features in the form of two rows of alternate cushions in some partially decayed specimens4 ,one of these is shown in fig4 #fjj2 the cushions are raised oval projections with a flat top1 and pieces of the rachis without pinnae might easily be mistaken for a ,coniferous stem4 ,zamites ,carruthersi ,seward4 ,a species founded on specimens from the ,wealden of ,sussex#aeai and recorded from ,kimmeridge beds in ,scotland#aebj1 characterised by linear or linear-elliptical pinnae attached obliquely to the outer part of the upper surface of the rachis1 somewhat abruptly narrowed at the proximal end but slightly broadened at the actual base 7fig4 #fja1 ,d1 ,e74 ,the pinnae appear to have been caducous and1 as in fig4 #fja1 ,d1 the position of an absciss-layer is occasionally visible4 ,in habit the fronds bear a close resemblance to those of ,encephalartos longifolius ,lehm4 ,the veins diverge from the base and are for the most part parallel1 though divergent at the bluntly rounded apex4 ,if1 as may be the case1 a specimen figured by ,hugh ,miller#aeba from ,scotland as ,zamites and subsequently named by ,richards#aebb ,podozamites ,milleri is identical with ,z4 ,carruthersi1 the specific name ,milleri has priority4 ,illustration3 ,fig4 #fja4 ,a-,c1 ,zamites ,buchianus4 ,d1 ,e1 ,zamites ,carruthersi4 ,f1 ,zamites ,zitteli4 7,a-,c after ,seward2 ,british ,museum2 ,a1 ,v4 #bcfc2 ,b1 ,v4 #babc;a2 ,c1 ,v4 #bbbg2 ,f1 after ,schenk47 ,zamites ,buchianus 7,ettingshausen74 ,illustration3 ,fig4 #fjb4 ,zamites ,buchianus4 7,british ,museum1 ,v4 #babj2 nat4 size47 ,a ,wealden and ,lower ,cretaceous species#aebc 7figs4 #fja1 ,a-,c2 #fjb7 represented in several ,european localities1 also in ,north ,america and ,japan1 reaching a length of over #gj cm42 in habit very similar to ,ceratozamia mexicana1 ,macrozamia ,macleayi and some other recent ,cycads4 ,the rachis has a fairly broad median groove on the upper surface2 pinnae alternate1 opposite or sub-opposite1 from #c to #bj cm4 long and from #ae to #b cm4 broad1 linear1 generally narrowed towards the base1 but in the more slender segments the reduction in breadth is less obvious2 attached obliquely to the rachis1 slightly thickened and broadened at the base 7fig4 #fja1 ,c71 separated from the rachis by a distinct absciss-layer and leaving an elliptical scar2 usually inclined at about #de but the angle varies considerably in different parts of a frond 7fig4 #fjb72 apices generally tapering to a point1 or more or less obtusely rounded2 veins numerous1 parallel1 and not as a rule prominent4 ,it is by no means unlikely that specimens figured by ,goeppert#aebd and some other authors as ,pterophyllum saxonicum or ,dioonites saxonicus are examples of this species4 ,fontaine#aebe speaks of ,dioonites ,buchianus as one of the most widely distributed and characteristic members of the ,potomac flora and it is described from ,japan by ,yokoyama#aebf and ,nathorst#aebg4 ,this type appears to be especially characteristic of ,wealden strata4 ,,otozamites4 ,braun4 ,braun#aebh proposed the name ,otozamites for certain ,mesozoic fronds formerly included in ,zamites1 one of his types being ,otozamites obtusus 7,lind4 and ,hutt47 7fig4 #fjc1 ,b7 originally regarded by ,brongniart as a ,fern and named ,filicites ,bucklandi#aebi4 ,the auriculate form of the base of the pinnae and the spreading veins were emphasised in the definition of the genus4 ,as in the case of many other ,cycadean fronds the limits of the genus are not always easy to define1 but as described below the genus is on the whole fairly distinctive4 ,it is a very widely spread ,jurassic type and extends from ,triassic to ,lower ,cretaceous rocks4 ,the supposed ,cretaceous species from ,greenland1 ,o4 groenlandica ,heer#aecj1 is probably not a plant-impression but a polished groove in the rock4 ,fronds pinnate1 reaching a length of #ej cm4 or more in some species2 pinnae alternate1 separate or contiguous and imbricate1 attached by a portion of the base to the upper surface of the rachis1 long and narrow 7fig4 #fjc1 ,a71 broadly oval or almost orbicular1 apex acute or obtuse1 base auriculate and asymmetrical#aeca1 the anterior lobe being more prominent than the posterior edge of the lamina which is usually rounded4 ,the veins radiate from the base and pass obliquely with occasional branching to the edge of the pinna2 in the more linear pinnae the veins may be parallel or nearly so4 ,zigno#aecb figured a piece of an ,otozamites frond from ,jurassic ,italian strata in connexion with a ,williamsonia and the actual specimen in the ,padua ,museum amply justifies the impression produced by the published drawing4 ,wieland's investigations#aecc in ,mexico have brought to light many cases of association of ,otozamites fronds and ,williamsonia flowers4 ,illustration3 ,fig4 #fjc4 ,a1 ,otozamites ,goeppertianus4 ,b1 ,otozamites obtusus 7 ,o4 ,bechei72 type-specimen4 7,a1 ,british ,museum1 ,v4 #bcfj2 ,b1 ,oxford ,museum47 ,the structure of the epidermis is partially described by ,schenk#aecd and more fully by ,thomas#aece3 the epidermal cells have sinuous walls and the stomata1 apparently confined to the lower surface1 have guard-cells with hemispherical or spindle-shaped thickened patches like those of some ,zamites fronds4 ,in one species1 ,o4 ,feistmanteli ,zig41 ,thomas found about #ajj stomata in #a sq4 mm4 of lamina forming almost contiguous lines between the veins4 ,in the account of the genus ,ptilophyllum reference is made to the occurrence of pinnae with asymmetrical and auriculate bases1 and it is only by the comparison of a large number of specimens that a distinction can be drawn between fronds that should be assigned to ,otozamites and forms of ,ptilophyllum which exhibit a well-marked tendency towards the ,otozamites type of pinna 7cf4 figs4 #eib1 #eic74 ,the variation in the form of the apices of pinnae and the relative position of the pinnae in different parts of the same frond are features worthy of notice in the determination of species#aecf4 ,the different appearance presented by an ,otozamites frond as viewed from the upper and lower face is illustrated in fig4 #fjd4 ,there are no recent ,cycads in which the segments have auriculate bases1 but in this feature as in the sinuous epidermal walls ,otozamites agrees with some species of the ,fern ,aneimia1 e4g4 ,a4 rotundifolia ,schrad4 7fig4 #bbc1 ,vol4 ii4 p4 #bhh74 ,illustration3 ,fig4 #fjd4 ,otozamites ,bechei4 ,a specimen in the ,bristol ,museum seen from below 7,a7 and above 7,b74 ,m4 ,s4 ,otozamites ,bechei ,brongniart4 ,there is considerable confusion in the nomenclature of this species described by ,brongniart#aecg from ,jurassic strata as ,filicites ,bechei3 in it ,brongniart included a specimen from the ,lias of ,axminster 7,dorsetshire7 previously figured by ,de la ,beche as a fossil ,fern4 ,it was on the ,axminster specimen that ,lindley and ,hutton founded the species ,otopteris obtusa#aech1 and as there is no doubt as to the specific identity of their type-specimen 7fig4 #fjc1 ,b7 and ,de la ,beche's fossil1 ,brongniart's designation has prior claim#aeci4 ,otozamites ,bechei is1 perhaps1 best regarded as a comprehensive type or a group-species in which numerous ,otozamites fronds described by authors1 on inadequate grounds1 as distinct species may well be included4 ,fronds agreeing generally with ,o4 ,bechei were very widely spread in ,rhaetic and ,jurassic floras4 ,specimens from the ,middle ,jurassic rocks of ,yorkshire have been described as ,otozamites obtusus var4 ooliticus#aedj to denote a slight difference in the form of the pinnae from the ,liassic fronds from ,dorsetshire2 but the distinctive features of the variety ooliticus are unimportant and hardly worthy of consideration in a general account of the species interpreted in a wide sense4 ,fronds pinnate2 pinnae usually more or less falcate1 occasionally straight and with parallel sides1 attached obliquely to the upper side of the rachis2 imbricate or separate1 the upper edge of the base of the lamina strongly auriculate1 the lower edge rounded2 apex obtuse2 veins strongly divergent especially in the lobed base and extending obliquely to the upper and lower edge of the lamina4 ,the specimen1 from the ,lias of ,lyme ,regis1 drawn in outline in fig4 #fje1 is an almost perfect frond3 the pinnae are obtusely pointed1 slightly falcate1 and there is a prominent lobe on the upper edge of the base of the laminae4 ,the ,jurassic species ,otozamites graphicus#aeda 7,leck4 ex ,bean ,,ms471 ,o4 vicetinus ,zig4#aedb1 ,o4 ,hennocquei#aedc 7,pom471 ,o4 recurrens ,sap41 ,o4 ,terquemi#aedd ,sap41 ,o4 linearis#aede ,halle1 are some of many examples of fronds agreeing closely with ,o4 ,bechei1 or in the case of ,o4 ,terquemi with ,o4 graphicus4 ,the fronds described by ,halle from ,graham ,land as ,o4 linearis afford a good illustration of the range of variation in the pinnae3 a characteristic feature is the considerable length1 exceeding #bj cm41 of the narrow linear fronds4 ,the impressions from the ,kome 7,cretaceous7 beds of ,greenland described by ,heer as ,glossozamites ,schenkii#aedf are probably closely allied to ,o4 ,bechei4 ,the ,rhaetic species ,o4 ,bucklandi ,schenk#aedg1 ,o4 indosinensis ,zeill4#aedh1 and ,o4 ,polakii ,krass#aedi1 illustrate older examples of closely allied types4 ,zeiller records ,otozamites pinnae similar to those of ,o4 indosinensis from ,rhaetic beds in ,persia#aeej4 ,otozamites ,beani 7,lindley and ,hutton74 ,illustration3 ,fig4 #fje4 ,otozamites ,bechei4 7,british ,museum1 #djfgb2 nat4 size47 ,founded on a specimen in the ,scarborough ,museum from the ,middle ,jurassic of ,yorkshire#aeea which is indistinguishable from ,leckenby's type-specimen of ,otopteris mediana#aeeb in the ,sedgwick ,museum1 ,cambridge4 ,long and narrow fronds exceeding #bj cm4 in length1 characterised by the broadly oval1 deltoid or sub-orbicular pinnae1 separate or partially imbricate and attached by a broad auriculate base2 apex bluntly rounded2 veins numerous and spreading from the base of the lamina4 ,the pinnae1 which may be #ce cm4 long and nearly #b cm4 broad1 are narrower and longer in the distal part of the frond 7fig4 #fjf74 ,the ,italian ,jurassic species ,otozamites molianus ,zig4#aeec1 recorded also from ,bornholm1 is a very similar type4 ,the generic name ,cyclozamia suggested by ,pomel for this form of frond has not been adopted though it is applied by ,schimper to ,o4 ,bunburyanus ,zig4 ,otozamites ,bunburyanus ,zigno4 ,a ,jurassic species#aeed similar in the long and narrow form of the frond to ,o4 ,beani but distinguished by the much smaller segments and by their more orbicular lamina 7fig4 #fjf1 ,b74 ,in habit the fronds agree closely with the ,fern ,nephrolepis ,duffi4 ,leckenby's species1 ,otopteris tenuata#aeee1 is probably the same as ,zigno's ,o4 ,bunburyanus1 the type-specimen of which in the ,padua ,museum consists of a long and narrow frond with leaflets not exceeding #h cm4 in length2 the rachis is hidden by the imbricate auriculate bases of the leaflets4 ,feistmantel#aeef refers to this species some pieces of very narrow fronds with overlapping pinnae from ,upper ,gondwana beds in ,india4 ,a still smaller form is described by ,mller#aeeg from ,bornholm as ,o4 tenuissimus1 and ,o4 ,bunburyanus is recorded from the same flora4 ,o4 ,feistmanteli ,zig4#aeeh agrees in the form of the frond and in its short and broad pinnae with ,o4 ,bunburyanus4 ,illustration3 ,fig4 #fjf4 ,a1 ,otozamites ,beani4 ,b1 ,otozamites ,bunburyanus4 ,illustration3 ,fig4 #fjg4 ,otozamites bengalensis4 7,indian ,geological ,survey1 ,calcutta2 nat4 size47 ,otozamites bengalensis 7,oldham and ,morris74 ,this ,indian species from the ,rajmahal ,hills#aeei and specimens of the same type from the ,cutch flora described as ,o4 contiguus ,feist4 afford another illustration of long and narrow fronds with short and relatively broad pinnae4 ,the drawings published by ,oldham and ,morris accurately represent the specimens3 the longest frond is #ba cm4 long and neither end is complete 7fig4 #fjg72 it is #i mm4 broad at the narrower end and #ae cm4 at the broader end4 ,the rachis is represented by a deep and broad groove2 the actual bases of the leaflets are not preserved1 but their position shows that they were attached to the upper face3 this is clearly seen in the specimen described by ,feistmantel as ,o4 contiguus which shows also that the lamina is auriculate at the upper edge of the base4 ,the pinnae vary in shape2 the smaller ones are characterised by a strongly curved lower margin and the upper edge is slightly curved or straight1 while the larger leaflets have more parallel edges and blunter rounded apices3 the latter form is well shown in the specimens unnecessarily distinguished by ,oldham and ,morris as var4 obtusa4 ,otozamites ,klipsteinii 7,dunker74 ,this ,wealden species1 first described by ,dunker as ,cyclopteris ,klipsteinii#aefj1 is remarkable for the large pinnae4 ,the rachis is fairly stout2 the broadly oval or oblong pinnae vary considerably in size and in the relation of breadth to length1 in rare cases reaching a length of over #h cm4 and a breadth of #bd cm42 apex obtuse1 base slightly auriculate and asymmetrical2 veins numerous1 radiating from the point of attachment to the margin of the lamina4 ,the occurrence of finer lines between the more prominent veins may indicate the presence of hypodermal stereome strands4 ,fig4 #fjh illustrates the striking variation in the size of the pinnae on a single frond and their attachment to the upper face of the rachis4 ,in the breadth of the segments ,o4 ,klipsteinii resembles ,o4 ,beani 7,lind4 and ,hutt471 ,o4 decorus ,sap4#aefa1 ,o4 lagotis ,brongn4#aefb and two species from ,south ,russia described by ,thomas#aefc as ,o4 ,izuimensis and ,o4 giganteus4 ,the pinnae of ,o4 giganteus exceed #aj cm4 in length and #c cm4 in breadth1 thus surpassing the largest segments of ,o4 ,klipsteinii4 ,some pinnae from the ,jurassic flora of ,oregon made by ,fontaine the type of a new species1 ,o4 oregonensis#aefd1 may be fragments of ,o4 ,klipsteinii4 ,nathorst#aefe records the occurrence in ,lower ,cretaceous or ,wealden beds in ,spitzbergen of ,cycadean leaflets very like those of ,o4 ,klipsteinii4 ,otozamites ,goeppertianus 7,dunker74 ,this ,wealden species1 named by ,dunker#aeff ,pterophyllum ,goeppertianum1 agrees in habit with some of those to which reference is made under ,o4 ,bechei1 e4g4 ,o4 linearis ,halle1 and represents a type of the genus with unusually narrow pinnae 7fig4 #fjc1 ,a74 ,the auriculate form of the lamina is feebly developed2 the linear-lanceolate pinnae are occasionally falcate and have acute apices2 as in many other species they were apparently deciduous4 ,it is by no means easy to distinguish some of these fronds from specimens included in ,ptilophyllum pecten4 ,illustration3 ,fig4 #fjh4 ,otozamites ,kliptsteini4 7,british ,museum1 ,v4 #cgji2 nat4 size47 ,,dictyozamites4 ,oldham4 ,this generic name was instituted#aefg for pinnate fronds from the ,rajmahal series of ,india1 assigned by ,feistmantel to a ,lower ,jurassic horizon1 but probably nearer in age to the ,middle ,jurassic series4 ,morris1 joint author with ,oldham of the ,memoir on the ,rajmahal plants1 adopted the name ,dictyopteris4 ,dictyozamites agrees very closely with ,otozamites but is readily distinguished by the anastomosing veins 7fig4 #fji71 while the absence of a midrib differentiates it from the ,palaeozoic genus ,dictyopteris4 ,the genus is recorded also from ,jurassic strata in ,england1 ,bornholm1 ,japan#aefh1 ,korea#aefi1 and from a locality #fj nautical miles ,n4,w4 of ,cape ,horn in ,tierra del ,fuego#aegj3 the specimens from these localities differ only in unimportant details from the ,indian type4 ,dictyozamites is confined to ,jurassic floras and appears to be especially characteristic of ,middle ,jurassic floras4 ,in ,india#aega fronds occur in close association with stems of the ,bucklandia type and1 although there is no proof of any connexion with stems or flowers1 it is probable that the fronds of this generic type were borne on stems similar to those of ,bucklandia and that the flowers were constructed on the ,williamsonia plan4 ,dictyozamites falcatus 7,morris74 ,morris#aegb described this ,rajmahal species under the names ,dictyopteris falcata and ,d4 falcata var4 obtusa2 the specimens were included by ,feistmantel under the designation ,dictyozamites indicus1 the original term falcata being discarded without adequate reason4 ,an examination of several of the figured fronds enables me to confirm the accuracy of the published drawings and to extend the description in a few particulars4 ,fronds pinnate of the habit of ,otozamites2 pinnae comparatively thick1 broadly linear1 alternate1 varying considerably in size and in the form of the apex which may be obtuse or acute4 ,the pinnae are attached by the middle part of the lamina only2 the upper edge of the base is slightly rounded or auriculate2 the lower angle is generally more definitely lobed4 ,the imbricate bases completely cover the upper face of the comparatively slender rachis4 ,the longest pinna seen on an ,indian frond is #f cm4 with a breadth of #b cm4 ,some of the pinnae on magnification exhibit a finely tuberculate appearance1 due no doubt to the presence of papillae on the epidermal cells like those on the pinnae of ,english and ,bornholm specimens4 ,this species is recorded by ,yokoyama#aegc from ,japan as ,d4 falcatus var4 distans1 and a similar form1 referred by him to a distinct species1 ,d4 grossinervis1 may be more appropriately named ,d4 falcatus var4 grossinervis#aegd4 ,the ,indian type occurs also in ,jurassic rocks of ,korea1 and ,halle has discovered some ,dictyozamites leaves in ,tierra del ,fuego#aege which he describes as ,dictyozamites sp4 cf4 ,d4 falcatus3 this record is of special interest from a phytogeographical point of view4 ,dictyozamites ,johnstrupi ,nathorst4 ,this species#aegf1 from rocks usually spoken of as ,liassic but not improbably ,middle ,jurassic in age1 differs from ,d4 falcatus in the slightly more falcate form of the pinnae and in the more strongly auriculate upper angle of the base of the lamina4 ,the stomata#aegg are confined to the lower epidermis and the strongly cuticularised guard-cells frequently lie at right-angles to the course of the veins4 ,the epidermal cells have very sinuous walls 7fig4 #fji1 ,c7 and in the middle of each is a prominent papilla4 ,dictyozamites ,hawelli ,seward4 ,this ,middle ,jurassic type from ,marske#aegh1 ,yorkshire1 differs from ,d4 falcatus in the relatively broader segments1 their straighter form 7fig4 #fji1 ,b71 and in the attachment to the rachis being slightly below the middle of the pinna base4 ,fig4 #fji1 ,a1 shows the base of a pinna and an oval scar similar to those on the rachis of some recent ,cycads 7cf4 fig4 #chg74 ,the epidermis is like that in ,d4 ,johnstrupi and as in that species the stomata are confined to the lower surface4 ,there are approximately #abj stomata per square millimetre2 each with two subsidiary cells 7fig4 #fji1 ,c7 of elongated form1 and the guard-cells have small thickened outgrowths or papillae as in ,d4 ,johnstrupi4 ,the epidermal features are described under ,d4 ,johnstrupi and ,d4 ,hawelli 7fig4 #fji1 ,c73 a fuller account of those in the latter species will be found in the paper by ,mr ,thomas and ,miss ,bancroft4 ,illustration3 ,fig4 #fji4 ,dictyozamites ,hawelli4 7,a1 ,b1 ,british ,museum2 ,c1 after ,thomas and ,bancroft47 ,,pterophyllum4 ,brongniart4 ,the name ,pterophyllum was first applied by ,brongniart#aegi to some fronds from the ,lias of ,hr1 which he named ,p4 majus and ,p4 minus1 species subsequently removed by ,nathorst#aehj to ,schimper's genus ,anomozamites4 ,brongniart#aeha defined ,pterophyllum fronds1 e4g4 ,p4 ,jaegeri 7fig4 #faj71 as pinnate1 bearing pinnules of almost equal breadth attached by the whole width of the base and with a truncate apex2 veins slender1 equal1 simple and slightly arched4 ,there has been considerable confusion and laxity in regard to the application of the name ,pterophyllum and in many cases no clear distinction has been recognised between this genus and ,nilssonia4 ,in ,nilssonia the distinctive feature is the complete absence of any rachis uncovered by the lamina on the upper face of well-preserved specimens1 while in ,pterophyllum the continuity of the lamina is broken by a greater or less breadth of rachis in the middle line of the frond2 the lamina does not cover the rachis but is attached laterally1 or at least the two laminae of the frond1 whether entire or deeply dissected1 do not meet in the middle of the rachis4 ,a specimen from the ,cretaceous of ,greenland described by ,heer as ,pterophyllum concinnum#aehb and now in the ,stockholm ,museum is probably a piece of a ,nilssonia2 the rachis is not exposed on the surface of the frond4 ,in ,nilssonia the veins are with few exceptions simple2 in ,pterophyllum they are often branched especially near their origin from the rachis3 in ,nilssonia the segments are of unequal breadth2 in ,pterophyllum they are usually equal4 ,it has been the practice of several authors to follow ,schimper#aehc in the employment of the generic name ,anomozamites for fronds with a more or less entire or irregularly pinnatisect lamina which bear a very close resemblance to ,nilssonia except that a portion of the rachis is exposed on the upper face4 ,potoni#aehd used ,pterophyllum in a wider sense including both fronds with equal pinnae and those of the ,anomozamites type3 this more extended use of ,pterophyllum is adopted by ,zeiller#aehe who prefers to retain ,anomozamites only as a sub-genus4 ,it is in this sense that the following definition is framed4 ,illustration3 ,fig4 #faj4 ,pterophyllum ,jaegeri4 ,from the ,keuper of ,lunz2 part of a frond #bce cm4 long and incomplete4 7,british ,museum1 ,v4 #ajdd2 nat4 size47 ,fronds pinnate2 pinnae linear1 attached by the whole base1 which may be enlarged2 the apex is truncate1 rounded1 or occasionally pointed2 the veins are simple or dichotomously branched and parallel to the edge of the lamina4 ,in some fronds 7sub-genus ,anomozamites7 the segments are unequal 7fig4 #fae71 short1 broad and truncate1 and the lamina may be entire or divided into a few very unequal segments4 ,the surface of the rachis is never completely covered by the lamina on the upper face of the frond and is often characterised by transverse wrinklings1 possibly due to the presence of ramental scales4 ,some interesting xerophilous features have recently been described by ,halle#aehf in the lamina of ,pterophyllum 7,anomozamites7 marginatum1 a ,rhaetic species figured by ,schenk and ,nathorst from ,franconia and ,scania4 ,the pinnae were thick and succulent4 ,stomata are confined to the lower surface and the edges of the upper face of the lamina form a rounded curve causing the thick upper cuticle to abut on the thinner stomatiferous lower cuticle1 thus producing in impressions the appearance of thickened margins4 ,there is no satisfactory evidence as to the nature of the reproductive organs or stems of the plants which bore fronds of the type represented by ,p4 ,jaegeri 7fig4 #faj7 and other forms with equal segments4 ,a stem referred by ,heer#aehg and by ,leuthardt#aehh to ,pterophyllum was not found in connexion with leaves1 and there is the same absence of any convincing evidence in the case of the imperfect specimens from the ,keuper of ,basel believed by ,leuthardt to be male and female inflorescences4 ,on the other hand leaves of ,anomozamites are known to have been borne on comparatively slender stems with dichasial branching1 and the reproductive shoots are of the same general type as those known as ,bennettites4 ,this discovery is due to ,nathorst who founded the genus ,wielandiella#aehi on fertile stems with ,anomozamites fronds4 ,mr ,thomas#aeij has recently obtained evidence from ,yorkshire ,jurassic material pointing to a similar connexion between ,anomozamites fronds and ,wielandiella stems4 ,pterophyllum is further distinguished from ,nilssonia by the folded walls of the epidermal cells and by the presence of two crescentic subsidiary cells 7fig4 #faa1 ,a7 instead of the ring of cells which surrounds the guard-cells in ,nilssonia 7fig4 #faa1 ,b74 ,schenk#aeia figured a few pieces of cuticle from fronds referred to ,pterophyllum in which the walls are more or less sinuous1 but the cells of ,pterophyllum crassinerve ,goepp4#aeib appear to have straight walls3 this species is1 however1 probably a ,nilssonia4 ,the stoma represented in fig4 #faa1 ,a1 is from the lower epidermis of ,pterophyllum 7,anomozamites7 ,nilssoni 7,phill47#aeic4 ,pterophyllum extends from ,upper ,carboniferous to ,lower ,cretaceous strata and is especially characteristic of ,keuper and ,rhaetic floras4 ,a possible representative of the sub-genus ,anomozamites is described by ,ettingshausen from ,tertiary beds in ,new ,south ,wales as ,anomozamites ,muelleri#aeid4 ,illustration3 ,fig4 #faa4 ,a1 ,pterophyllum ,nilssoni2 ,b1 ,nilssonia mediana4 7,after ,thomas and ,bancroft47 ,pterophyllum ,fayoli ,renault and ,zeiller4 ,this species#aeie was founded on a large frond from the ,commentry coalfield with a stout rachis bearing linear pinnae1 attached along a narrow groove on its outer edge1 reaching a length of #ab cm4 and a breadth of #a cm42 adjacent pinnae are united at the base4 ,the apices are pointed and there are #aj-ab unbranched veins in the lamina4 ,fig4 #fab shows a small piece of the large specimen in the ,natural ,history ,museum1 ,paris4 ,pterophyllum sp4 ,arber4 ,the only representative of a ,carboniferous frond of ,cycadean habit discovered in ,britain is that recorded by ,arber#aeif from ,westphalian strata at a depth of #ahcd ft at ,barfreston in ,kent4 ,a fairly stout rachis bears incomplete pinnae the longest of which is slightly more than #a cm4 in length and #a-ae cm4 broad2 each segment1 very slightly contracted at the base1 has #c-d occasionally forked veins4 ,arber compares the fragments with ,pterophyllum blechnoides ,sand4 from ,germany#aeig4 ,pterophyllum ,cambryi ,renault4 ,this ,permian species from ,autun#aeih is similar to ,p4 ,fayoli1 but differs in the more slender rachis and in the finer venation of the linear1 acute1 pinnae4 ,the pinnae in ,renault's specimen reach a length of #dh cm4 and are from #ce-d mm4 broad2 they are slightly confluent at the base and the veins occasionally fork4 ,illustration3 ,fig4 #fab4 ,pterophyllum ,fayoli4 7,from the type-specimen1 ,paris2 nat4 size47 ,among other ,palaeozoic species are ,pterophyllum ,grand',euryanum ,sap4 and ,mar4#aeii discovered by ,grand',eury in the ,coal ,measures of ,france1 ,p4 blechnoides ,sand4#afjj from the ,upper ,coal ,measures of ,oppenau and recorded by ,geinitz#afja from the ,middle ,permian of ,germany1 ,p4 ,cottaeanum ,gutb4#afjb1 a similar type1 also from ,permian rocks1 but with coarser venation4 ,the specimens figured by ,geinitz as ,p4 blechnoides and ,p4 ,cottaeanum are in the ,dresden ,museum3 the former species is represented by a good impression on shale which shows the generic characters very clearly4 ,pterophyllum ,jaegeri ,brongniart4 ,brongniart#afjc founded this species 7fig4 #faj7 on material from the ,keuper of ,stuttgart4 ,the fronds are characterised by the relatively narrow parallel-sided pinnae with rounded or truncate apices and little or no basal contraction2 the pinnae may be contiguous or separate4 ,there are #ad-af veins in each pinna4 ,leuthardt#afjd1 who figures several examples of this species from ,keuper strata at ,basel1 speaks of the breadth-index of the pinnae as #ab1 a term employed to denote the relation of the breadth to the length of a segment4 ,pterophyllum longifolium#afje is a very similar ,keuper type3 in this species the pinnae are rather shorter and broader than in ,p4 ,jaegeri and contracted at the base2 the apex is truncate or obtuse4 ,the differences between these species is1 however1 very trifling4 ,the imperfectly preserved fossils figured by ,leuthardt#afjf as the inflorescences of ,pterophyllum have not been found in connexion with fronds and their nature is problematical4 ,this and other species are recorded by ,krasser#afjg from the ,lunz beds in ,austria4 ,pterophyllum ,bronni ,schenk4 ,a ,keuper species#afjh from ,raibl in ,carinthia distinguished by its large pinnae1 #ae cm4 or more in length and #je cm4 broad1 and by their almost digitate disposition on the rachis4 ,the fronds appear to be relatively short3 the upper pinnae are highly inclined while the lower are given off at an obtuse angle2 they are obcuneate or more or less oblanceolate1 with a truncate asymmetrical apex and rounded angles2 the base is slightly contracted4 ,arber#afji has figured some specimens from the ,munich ,museum in one of which there are five spreading pinnae and a portion of the rachis2 one pinna is undoubtedly attached and the others1 though probably in place1 are not in actual connexion with the axis4 ,there is a close resemblance between this species and ,sphenozamites ,rogersianus ,font4#afaj3 in the ,american type the fronds must have been #a met4 long2 the leaflets1 #ai #i cm41 are elliptical1 broadest near the apex and attached by the middle of the rounded base4 ,between the divergent and forked veins there is a fine granulation probably due to the presence of papillae4 ,pterophyllum ,bronni and ,p4 ,rogersianum might be placed in ,schimper's genus ,macropterygium#afaa1 though another ,raibl species1 originally described by ,schenk as ,pterophyllum giganteum#afab and referred by ,schimper to ,macropterygium1 has much longer and relatively narrow pinnae and agrees more closely with ,pterophyllum as the genus is usually defined4 ,in order to emphasise the distinctive features of ,pterophyllum ,bronni and ,fontaine's ,virginian species they may conveniently be spoken of as ,pterophyllum 7,macropterygium7 ,bronni and ,pterophyllum 7,macropterygium7 ,rogersianum4 ,illustration3 ,fig4 #fac4 ,pterophyllum ,braunianum4 7,a1 nat4 size2 ,b1 enlarged2 after ,schenk47 ,pterophyllum ,braunianum ,goeppert4 ,in this ,rhaetic species#afac 7fig4 #fac7 the narrow linear pinnae1 contiguous or more or less distant1 are #a-b mm4 broad and may exceed #e cm4 in length though they are usually shorter2 they are attached more or less at right-angles to the sides of a transversely wrinkled rachis4 ,the base of the lamina is broadened and the veins are parallel1 simple or forked4 ,the epidermal cells have sinuous walls4 ,pterophyllum ,tietzei ,schenk4 ,a ,rhaetic species founded#afad on specimens from ,persia and described also by ,zeiller#afae from ,tonkin represented by fronds #a met4 long and at least #ae cm4 broad4 ,the segments1 #c-g cm4 long and #h-ah mm4 broad1 are often set at right-angles to the rachis2 the edges are parallel but the lower edge bends upwards at the apex4 ,the veins are simple or forked and approximately #jc mm4 apart4 ,pterophyllum ,bavieri ,zeiller4 ,this ,rhaetic species from ,tonkin#afaf and ,persia#afag is interesting as affording an example of a frond with exceptionally narrow and contiguous pinnae4 ,the frond is narrow and lanceolate1 #ae-bj cm4 long with pinnae normal to the rachis1 #e-a mm4 broad and #g-be mm4 long attached by the whole base which is sometimes slightly enlarged4 ,the veins are simple or forked1 #ae-be mm4 apart3 the apices of the segments are rounded or truncate and the form of the whole is similar to that of ,pterophyllum aequale but narrower4 ,pterophyllum 7,anomozamites7 inconstans ,braun4 ,in habit this ,rhaetic species#afah resembles ,nilssonia compta4 ,the linear-lanceolate fronds1 as described by ,zeiller#afai in his ,tonkin memoir1 attain a length of #bj cm4 and a breadth of #d cm4 ,the rachis1 characterised by numerous transverse ridges1 bears alternate or sub-opposite leaflets often at right-angles2 they are almost rectangular and hardly longer than broad1 attached by the whole of the base1 which may be broadened1 to the upper face of the rachis1 but the lamina does not cover the whole of the rachis as in ,nilssonia4 ,the pinnae vary in breadth on the same frond and occasionally the lamina is continuous as in some forms of ,nilssonia4 ,schenk#afbj figures examples from the ,rhaetic of ,franconia in which the lamina is very irregularly dissected and may be entire for a considerable distance4 ,the epidermal cells have slightly sinuous walls4 ,a similar type is represented by ,pterophyllum 7,anomozamites7 ,schenki ,zeill4#afba1 but the segments are contracted basally and become wider towards the apex where1 as in ,p4 inconstans1 the edges are parallel4 ,feistmantel's species ,platypterygium ,balli#afbb1 though superficially similar to ,pterophyllum1 appears to agree more closely with ,pseudoctenis4 ,illustration3 ,fig4 #fad4 ,a1 ,b1 ,pterophyllum ,nathorsti2 ,a from below2 ,b from above4 ,c1 ,nilssonia tenuicaulis4 7,a1 ,b1 ,gunn ,collection1 ,british ,museum2 ,c1 ,arber ,coll4 ,sedgwick ,museum1 #eci2 nat4 size47 ,pterophyllum ,nathorsti ,seward4 ,this species1 founded on a specimen in the ,sedgwick ,museum1 ,cambridge1 from the ,middle ,jurassic beds of ,yorkshire1 was formerly referred to the genus ,dioonites#afbc1 but since the ,yorkshire specimens were supplemented by material from ,kimmeridge strata in ,scotland#afbd affording more definite information with regard to the attachment of the pinnae it has been transferred to ,pterophyllum4 ,pinnae laterally attached to the rachis which in some specimens shows a transverse wrinkling1 narrow1 linear1 #c-d mm4 wide and reaching a length of #i cm4 ,the base of the segments is slightly expanded2 the apex is acuminate or bluntly pointed3 there are approximately three veins in #a mm4 of lamina4 ,this type 7fig4 #fad1 ,a1 ,b7 is similar to ,pterophyllum aequale ,brongn4 as figured by ,zeiller#afbe from the ,rhaetic of ,tonkin and agrees closely with some of the large ,rhaetic specimens referred by ,schenk to ,p4 ,braunianum4 ,the ,jurassic fronds from ,oregon described by ,fontaine#afbf as ,ctenophyllum angustifolium are similar forms and a specimen from the ,wealden of ,germany included by ,schenk in ,p4 ,dunkerianum#afbg should probably be included in this species4 ,other closely allied forms are represented by ,p4 distans ,old4 and ,morr4#afbh and ,p4 ,footeanum from ,india4 ,illustration3 ,fig4 #fae4 ,pterophyllum 7,anomozamites7 ,nilssoni4 7,british ,museum1 #ci1cjf2 nat4 size47 ,illustration3 ,fig4 #faf4 ,pterophyllum 7,anomozamites7 ,lyellianum4 7,geological ,survey ,museum1 #fcif2 nat4 size47 ,pterophyllum 7,anomozamites7 ,nilssoni 7,phillips74 ,the type-specimen1 from the ,jurassic beds on the ,yorkshire coast and now in the ,york ,museum1 was described by ,phillips#afbi as ,aspleniopteris ,nilssoni and placed in ,pterophyllum by ,lindley and ,hutton and many other authors#afcj4 ,the fronds are linear2 the lamina may be almost entire or divided into unequal deep truncate segments2 the veins are simple or dichotomously branched 7fig4 #fae74 ,the leaves are very similar to those of ,nilssonia2 they were probably borne on stems similar to those described by ,nathorst as ,wielandiella4 ,reference is made to the structure of the epidermal cells in the account of the genus4 ,pterophyllum 7,anomozamites7 ,lyellianum 7,dunker74 ,this ,wealden species1 originally referred by ,dunker#afca to ,pterophyllum1 was afterwards transferred to ,anomozamites#afcb4 ,the fronds1 in habit resembling the larger ,rhaetic species ,p4 ,braunianum ,goepp41 are characterised by the narrow linear pinnae of almost equal breadth attached approximately at right angles2 there is a narrow line of rachis separating the two rows of segments 7fig4 #faf74 ,,cycadites4 ,sternberg4 ,,pseudocycas4 ,nathorst4 ,the generic name ,cycadites was first used by ,sternberg#afcc though it has since been shown that the specimens for which he proposed it belong to other genera4 ,as employed by ,brongniart#afcd and other authors ,cycadites stands for fossil fronds agreeing in habit with the pinnate leaves of recent species of ,cycas 7fig4 #chg1 ,a72 the presence of a single median in the linear pinnae is generally regarded as an essential feature4 ,cycadites may be defined as follows3 ,fronds pinnate2 pinnae alternate or opposite1 linear entire1 with a midrib and no lateral veins1 attached to the rachis by the entire base1 the lower margin of which may be slightly decurrent or narrowed near the point of attachment4 ,epidermal cells with straight walls and stomata agreeing in structure with those of the recent genus4 ,as thus defined1 including the characters of the epidermal cells1 the genus has no representatives2 but the generic name should also be applied1 as ,miss ,holden#afce has recently suggested1 to fronds of the ,cycas form which afford no information with regard to the structure of the epidermis4 ,the resemblance of ,cycadites fronds to those of ,cycas1 coupled with the fact that impressions superficially resembling megasporophylls of the recent genus are recorded from ,mesozoic strata1 was considered sufficient justification for the employment of a name implying close affinity to or even generic identity with ,cycas4 ,a fuller knowledge of the epidermal characters of some of the fronds hitherto included in ,cycadites has necessitated the substitution of a new genus for ,cycadites4 ,an examination by ,nathorst#afcf of ,heer's ,lower ,cretaceous ,greenland species ,cycadites ,steenstrupi and of other fronds showed that the epidermal cell-walls are sinuous and the stomata arranged differently from those of ,cycas4 ,for these and other reasons ,nathorst proposed a new name ,pseudocycas4 ,he also pointed out that the pinnae in the fossil fronds have as a rule a double #8midrib4' ,nathorst's discovery raised the question whether other fronds described as ,cycadites should be transferred to ,pseudocycas4 ,miss ,holden's investigation of other supposed ,mesozoic representatives of ,cycas leads to the conclusion that #8it is not impossible that all ,mesozoic specimens of ,cycadites will turn out to be ,pseudocycas4' ,this observer shows that ,cycadites ,saportae ,sew4 and ,c4 ,roemeri ,schk4 agree in the sinuous walls of the epidermal cells with ,pseudocycas2 and so far no species of ,cycadites1 in which it was possible to examine the cuticular membrane1 has been found that does not conform to ,nathorst's definition of ,pseudocycas at least as regards the structure of the epidermal cells4 ,nathorst defined ,pseudocycas in the following sense3 ,fronds similar to those of ,cycadites and ,cycas but with pinnae characterised by a double #8midrib1' the stomata being confined or almost confined to the groove between the two #8midribs4' ,nathorst also notes that in ,pseudocycas the bases of the pinnae are not contracted as is often the case in ,cycadites and ,cycas1 but this is a feature of secondary importance4 ,miss ,holden has1 however1 expressed the opinion that the double #8midrib' is an untrustworthy character and that the stomata are not always arranged as in the fronds examined by ,nathorst4 ,nathorst states that in ,pseudocycas ,steenstrupi and ,p4 insignis the midrib though usually double may be single3 the same variation occurs in ,p4 ,saportae4 ,miss ,holden found that an impression made from a pinna of ,cycas siamensis showed a double line on the upper face and a single rib on the lower2 that is ,pseudocycas and ,cycas characters occur on a single pinna4 ,on drying1 the ridge on the lower face of the lamina collapses and a groove is formed bounded by two ridges4 ,in a recently published and interesting paper on #8,some ,xerophytic ,leaf-structures in ,mesozoic ,plants1' ,dr ,halle#afcg makes some important additions to our knowledge of ,pseudocycas4 ,he agrees with ,miss ,holden's views with regard to the use of the generic names ,pseudocycas and ,cycadites1 but dissents from her interpretation of the median groove as the result of shrinkage of a midrib4 ,part of the evidence presented by ,halle is based on the structure of the leaf-cuticle as shown in microtome sections#afch4 ,he found that a distinct median groove is always present on the pinnae of ,pseudocycas insignis and other species4 ,if the groove were due to collapse of the tissue of a true median rib the presence of stomata--which in ,p4 insignis are confined to the middle line of the lamina--below the vein would be an unusual feature4 ,he found no indication of a median vein or of any vascular tissue4 ,all that is revealed by an examination of the cuticle is that the lamina has a well-defined groove bounded by prominent ridges1 and in ,pseudocycas ,roemeri the groove is deeper and is formed by the bending-back of the lamina4 ,the stomata are practically confined to the groove and in ,p4 insignis and ,p4 ,steenstrupi an additional protection against excessive transpiration was afforded by elongated papillae4 ,in the sinuous walls of the epidermal cells and in the structure of the stomata ,pseudocycas agrees with the ,bennettitalean type as defined by ,thomas and ,bancroft#afci4 ,the #8midrib' of the pinnae marks the position of a pronounced groove and we have no information with regard to the venation4 ,as ,halle says1 protection against drought is afforded by #8other means than those usual among existing ,cycads1' which provide against excessive transpiration by the sinking of the individual stomata below the surface4 ,the epidermal features of ,pseudocycas afford a striking example of the danger of basing conclusions on mere impressions and they further emphasise the great difference between ,mesozoic ,cycadean fronds and those of recent genera4 ,we have no knowledge of the nature of the reproductive organs of the plants which bore ,pseudocycas fronds1 but the agreement of the stomata and epidermal cells with those in some ,bennettitalean types favours the inclusion of the genus in that class4 ,it has previously been pointed out that the impression figured by ,heer#afdj in close association with the ,greenland specimens of ,pseudocycas ,steenstrupi as a carpellary leaf of the ,cycas type is much too imperfect to be identified and has no claim1 as an examination of the actual specimen in the ,copenhagen ,museum convinced me1 to be compared with a megasporophyll of ,cycas4 ,this view is shared by ,nathorst4 ,in some cases the name ,cycadites has been applied to fragments that might equally well belong to ,conifers or other plants1 and not infrequently a careful examination of fossils referred to ,cycadites shows that the pinnae afford no evidence of a true midrib4 ,casts of revolute pinnae like those of the recent species ,encephalartos ,ghellinckii 7fig4 #chb7 would present an appearance closely resembling a strong midrib4 ,heer's ,siberian ,jurassic species ,cycadites sibiricus#afda is probably a piece of a ,taeniopteris or ,nilssonia frond1 and ,c4 gramineus ,heer#afdb should be referred to ,taxites4 ,an examination of the ,indian fronds described by ,oldham and ,morris and ,feistmantel as species of ,cycadites leads me to discard all of them as trustworthy records of the genus3 in ,cycadites confertus#afdc and ,c4 ,blandfordianus#afdd there appear to be several veins in the pinnae and not a single midrib4 ,cycadites constrictus#afde is almost certainly a ,conifer as ,nathorst has also suggested4 ,no satisfactory example of ,cycadites has been described from ,palaeozoic strata2 ,goeppert's ,cycadites gyrosus#afdf is founded on material too imperfect to determine1 and an examination of his ,culm species ,c4 taxodinus in the ,breslau ,museum led me to refer it to a ,conifer4 ,the specimens figured#afdg by ,zeiller from ,lower ,gondwana rocks in ,india as ,cycadites8 sp4 are portions of linear leaves or leaflets #e mm4 broad with a median rib but they can hardly be accepted as evidence of the presence of a ,cycadean plant4 ,illustration3 ,fig4 #fag4 ,pseudocycas insignis4 ,from the ,lias of ,hr4 ,a1 nat4 size2 ,b1 ca4 #b4 7,after ,nathorst47 ,pseudocycas insignis ,nathorst4 ,the fronds of this ,cenomanian species from the ,west of ,greenland reach a breadth of #af cm42 the rachis1 #a cm4 broad1 has two parallel ridges on the upper surface and to these are attached at a wide angle the broad bases of narrow linear pinnae reaching a length of #i cm4 and a breadth of #b-c mm4 7fig4 #fag74 ,the pinnae are thick and separate and each has a double #8midrib' consisting of two parallel lines 7fig4 #fag1 ,b7 which are occasionally replaced by one4 ,the so-called double #8midrib' represents the two prominent ridges bordering the groove4 ,the stomata1 confined to the median groove1 are approximately circular and the short epidermal cells have sinuous walls#afdh4 ,pseudocycas ,steenstrupi 7,heer74 ,nathorst refers this species1 described by ,heer as ,cycadites1 from the ,cenomanian of ,greenland1 to ,pseudocycas on the ground that the epidermal cells are like those of ,p4 ,steenstrupi and the stomata are confined to a median groove4 ,heer figures an impression in close association with the frond of this species which he identifies1 without any adequate reason1 as a carpellary leaf like that of a ,cycas4 ,pseudocycas ,saportae 7,seward74 ,it has recently been shown by ,miss ,holden that this ,wealden ,english species#afdi has the epidermal characters of ,pseudocycas4 ,in external form it agrees closely with ,cycadites tenuisectus ,sap4#afej from ,lower ,cretaceous rocks in ,portugal1 but nothing is known of the epidermal features of the latter type4 ,the rachis is broad and flattened and bears alternate or sub-opposite pinnae of uniform breadth attached at right-angles or obliquely to its upper surface 7fig4 #fah74 ,the pinnae are #f-g cm4 long and about #a mm4 broad2 their bases are slightly expanded and the apices sharply pointed4 ,miss ,holden#afea finds that the median rib is sometimes double and that the middle region of the lamina is covered with stomata2 the epidermal cells have sinuous walls and stomata occasionally occur on each side of the main median stomatal area4 ,dr4 ,halle#afeb of ,stockholm1 who has examined cuticular preparations made from ,english specimens1 confirms ,miss ,holden's observations as regards the stomata1 but he shows that there is no evidence of the existence of a midrib in the strict sense1 the appearance of a single or double median vein being due to the presence of a dorsal stomatiferous groove1 the edges of which would produce an impression on the matrix of a double vein or1 if the groove became narrower1 the impression would suggest a single midrib4 ,illustration3 ,fig4 #fah4 ,pseudocycas ,saportae4 ,from the ,wealden1 near ,hastings4 7,british ,museum1 ,v4 #bggg2 nat4 size47 ,pseudocycas ,roemeri 7,schenk74 ,this ,wealden species recorded from ,north ,germany#afec and the ,sussex coast#afed has broader pinnae laterally attached to the rachis4 ,miss ,holden describes the stomata as covering the whole lower surface of the pinnae except over the midrib4 ,this description must be revised in the light of ,halle's results obtained from an examination of the cuticle of the type-specimen of the species in the ,berlin ,museum4 ,he finds that the edges of the pinnae are strongly revolute and thus form a deep dorsal canal which is almost closed#afee1 a form of lamina1 as seen in section1 very similar to that of an ,empetrum leaf4 ,the stomata are confined to the groove4 ,it may be that the specimen examined by ,miss ,holden is specifically distinct or1 as ,halle also suggests1 the cuticle obtained from the ,english fossil may not represent the whole surface but only the walls of the canal with possibly a portion of the cuticle of the outer dorsal surface4 ,this type of leaf described by ,halle is similar to that of ,p4 insignis with the xerophilous character intensified4 ,cycadites ,saladini ,zeiller4 ,this species was founded by ,zeiller#afef on fronds from the ,rhaetic of ,tonkin reaching a length of #dj cm4 and #b-he cm4 broad with a rachis #c-d mm4 wide bearing contiguous linear pinnae #ae-de cm4 long and #ae-c mm4 broad with a more or less contracted base and a rounded or obtusely pointed apex4 ,the pinnae are attached almost at right-angles or at an angle of #fj-hj4 ,there is a clearly defined midrib4 ,it is not improbable that were the structure of the epidermal cells known this species would be found to be another example of ,pseudocycas4 ,cycadites rectangularis ,brauns4 ,this species#afeg1 first recorded from ,rhaetic strata in ,germany1 differs in the narrower and more acutely pointed pinnae from ,c4 ,saladini4 ,miss ,holden describes the midrib as double1 but until specimens are found which admit of an examination of the cuticles it is impossible to decide whether it should be transferred to ,pseudocycas4 ,the species is widely distributed in ,rhaetic and ,jurassic strata and specimens are recorded from the ,lias of ,lyme ,regis on the south coast of ,england4 ,cycadites ,renaulti ,lignier4 ,this species1 from the ,middle ,lias of ,normandy#afeh1 is founded on fronds #bb-bf cm4 broad with a rachis #c mm4 in breadth bearing laterally-inserted pinnae almost at right-angles #aa-ab mm4 long and #abe-aej mm4 broad2 it is very similar to ,c4 rectangularis which occurs in the same beds4 ,,ii4 ,nilssoniales4 ,,nilssonia4 ,brongniart4 ,this genus#afei was named after the ,swedish naturalist ,nilsson who had figured certain plants from the ,lias of ,hr referred by ,fries to the ,ferns3 these were named by ,brongniart ,nilssonia brevis and ,n4 elongata and classed with the ,cycads4 ,the type-specimens of the latter species are regarded by ,nathorst as a form of ,n4 brevis4 ,the history of the genus is fully discussed in ,nathorst's able monograph#affj4 ,nilssonia1 founded on fronds which with one exception are known only as casts or impressions1 may be thus defined3 ,fronds with circinate vernation1 at least in the type-species ,nilssonia brevis 7fig4 #fai1 ,c1 ,d71 similar in shape to the leaves of ,scolopendrium vulgare and ,polypodium irioides and to such unusual forms of ,cycas fronds as those reproduced in figs4 #chd1 #chg1 ,i#affa1 in which the laminae of the pinnae are concrescent and form a continuous or deeply cut lamina4 ,they may reach a length of #fj cm4 and a breadth of #aj cm4 and some specimens are known in which the leaf is less than #a cm4 in width4 ,the lamina is occasionally entire1 but in the great majority of cases it is more or less deeply cut into segments of unequal breadth varying considerably in size and shape even in the same species1 usually deep and truncate and sometimes long and narrow 7e4g4 ,n4 pterophylloides1 fig4 #fai1 ,b74 ,an important distinguishing feature is the attachment of the lamina to the upper face of the rachis which it covers3 the extension of the lamina over the surface of the frond axis and the rare occurrence of branching of the veins are characters in which ,nilssonia differs from ,taeniopteris4 ,the veins are given off at right-angles or obliquely from a very narrow groove occupying the median line of the rachis2 they are nearly always simple and in some of the more fleshy leaves1 e4g4 ,n4 brevis1 they are seldom visible4 ,the surface of the lamina may be smooth or transversely corrugated4 ,the rachis forms a prominent rib on the under surface of the frond 7fig4 #fbj1 ,a7 and may be continued beyond the lamina as a short petiole4 ,epidermal cells polygonal or rectangular1 with straight walls in contrast to the sinuous walls of ,taeniopteris2 some of the cells bear strongly cuticularised papillae1 possibly the bases of hairs 7compare the hairs on the fronds of ,acrostichum crinitum1 a ,fern with leaves similar in shape to some of the large entire fronds of ,n4 orientalis though relatively broader and with anastomosing veins74 ,stomata usually confined to the lower epidermis and not very numerous2 guard-cells of rounded contour and without any special thickening surrounded by #f-h accessory cells with thickened walls 7fig4 #faa1 ,b7 forming a chimney slightly raised over the stomatal pore#affb4 ,in ,nilssonia the guard-cells do not exhibit that regularity of orientation which characterises the stomata of ,ptilophyllum1 ,otozamites1 and other ,bennettitalean fronds4 ,little is known of the anatomy of the leaves3 in a petrified leaf of ,n4 orientalis#affc from ,upper ,cretaceous rocks in ,japan there is no palisade-tissue and small groups of sclerenchyma occur above and below the veins4 ,the xylem appears to be centripetal1 but the preservation is far from satisfactory4 ,a few secretory canals were found near the edge of the leaf4 ,we have no certain knowledge of the reproductive organs4 ,the small circular projections figured by ,schenk#affd on some leaves of ,nilssonia polymorpha as sporangia have no claim to be so regarded4 ,in the description of ,n4 brevis reference is made to some seeds discovered by ,nathorst which may belong to that species4 ,nathorst suggests the possibility that the ,rhaetic fossil ,stenorrachis scanicus ,nath4 may be the seed-bearing shoot of a ,nilssonia1 either ,n4 brevis or ,n4 polymorpha1 and if this surmise is correct it almost necessarily involves the genus ,beania#affe which has been tentatively referred to the ,ginkgoales though without any convincing evidence to support such connexion4 ,nothing is known of the stems3 the occasional occurrence of leaves converging towards a common support points to a ,cycadean habit4 ,it is possible1 as ,nathorst suggests1 that the ,rhaetic species ,bucklandia ,saportana#afff may be the stem of a ,nilssonia4 ,illustration3 ,fig4 #fai4 ,a1 seed 7,nilssonia872 ,b1 ,nilssonia pterophylloides2 ,c1 ,d1 ,nilssonia brevis2 ,e1 ,n4 polymorpha4 7,a-,d nat4 size2 ,e1 slightly enlarged2 after ,nathorst47 ,nilssonia is especially characteristic of ,jurassic and ,rhaetic floras2 it occurs also in ,triassic beds and extends into ,cretaceous floras4 ,nathorst instituted the genus ,nilssoniopteris#affg for some specimens from the ,yorkshire coast which he believed to be examples of ,nilssonia tenuinervis on the ground that the veins are dichotomously branched and the epidermal cells have sinuous walls4 ,mr ,hamshaw ,thomas#affh has1 however1 shown by an examination of the specimens in the ,stockholm ,museum that they belong to ,taeniopteris vittata1 and ,prof4 ,nathorst agrees with this conclusion4 ,the name ,nilssoniopteris must therefore be abandoned4 ,miquel#affi proposed the name ,hisingera for some ,nilssonia fronds1 but it has not been adopted4 ,nilssonia polymorpha ,schenk4 ,linear fronds varying considerably in breadth and in the degree of dissection of the lamina1 which may be entire2 the margin may show broad and shallow crenulations or there may be a few narrow and deep sinuses cutting the otherwise entire lamina into long and narrow segments4 ,more usually the lamina is divided to the rachis into numerous truncate segments traversed by parallel1 simple1 veins extending from a narrow groove in the middle of the rachis on the upper surface of the frond 7fig4 #fai1 ,e74 ,the veins run in very narrow grooves in the generally flat but occasionally corrugated lamina#afgj4 ,this species agrees very closely in habit with ,n4 compta and ,n4 brevis and1 as ,nathorst points out1 it is in some cases almost impossible to distinguish ,nilssonia polymorpha from ,n4 brevis4 ,some of the fronds from the ,rhaetic of ,franconia described by ,schenk as ,n4 polymorpha are examples of ,n4 brevis4 ,in ,n4 polymorpha the distal ends of the segments are blunter1 the lamina is much less folded and when folds or corrugations occur they are less regular than in ,n4 brevis4 ,the epidermal cells are polygonal and have thick1 straight1 walls3 oval or circular papillae occur both on the lamina and rachis4 ,the stomata1 confined to the lower surface1 are between the veins and each is accompanied by a ring of subsidiary cells 7cf4 fig4 #faa1 ,b74 ,n4 polymorpha is a member of ,rhaetic floras and is recorded also from ,liassic rocks at ,hr#afga4 ,illustration3 ,fig4 #fbj4 ,a1 ,b1 ,nilssonia brevis2 ,a1 section of the frond2 ,b1 section of the lamina parallel to the rachis4 ,c1 ,n4 saighensis4 7,a1 ,b1 after ,nathorst47 ,nilssonia brevis ,brongniart4 ,this species#afgb 7fig4 #fai1 ,c1 ,d71 one of those from ,hr on which the genus was founded1 has been very fully investigated by ,nathorst#afgc whose researches have cleared up many obscure features4 ,the young fronds are circinate like those of ,ferns and ,cycas4 ,the linear fronds agree generally in habit with those of ,n4 polymorpha and ,n4 compta1 but the lamina is thicker and is characterised by regular transverse corrugations2 the veins are very rarely visible except in young leaves which have not reached their full thickness4 ,the fronds may be #ej cm4 long and vary in breadth from #ae to #ab cm42 the petiole is very short or the frond may be sessile4 ,between the regular grooves on the upper surface the lamina is more or less convex2 seen from below the grooves are represented by ridges and between each pair of ridges there are parallel folds1 sometimes three 7fig4 #fbj1 ,b7 or as many as six2 and where the segments are narrow1 that is the strips of lamina between two grooves 7or ridges71 there may be only a single fold which gives the appearance of linear segments with a single midrib as in ,cycadites1 a misleading resemblance of special interest in reference to the ,nilssonia fronds described by ,oldham and ,morris#afgd and by ,feistmantel#afge as ,cycadites rajmahalensis4 ,owing to the fleshy nature of the leaf the difference between the upper and lower side is particularly well marked in this species4 ,the lamina may be more or less entire1 but is usually divided by deep sinuses extending to the rachis into truncate or distally tapered segments varying in breadth 7fig4 #fai1 ,c1 ,d71 the narrow segments being characterised by a more pointed apex than in ,n4 polymorpha4 ,the structure of the stomata and epidermal cells is of the type described in the definition of the genus4 ,strongly cuticularised papillae1 incorrectly described by ,schenk#afgf in ,n4 polymorpha as stomata1 occur on some of the epidermal cells3 these may be the bases of hairs4 ,in some preparations ,nathorst found patches of a resinous substance1 an interesting discovery in view of the occurrence of secretory canals in the petrified leaf of ,nilssonia orientalis described by ,dr ,stopes#afgg4 ,illustration3 ,fig4 #fba4 ,nilssonia rajmahalensis 7 ,cycadites rajmahalensis74 7,indian ,geological ,survey1 ,calcutta2 nat4 size47 ,nilssonia brevis occurs in ,upper ,rhaetic and ,lower ,liassic strata4 ,nilssonia pterophylloides ,nathorst4 ,a ,rhaetic ,scanian species originally referred by ,nathorst#afgh to ,nilssonia but later removed by him to ,dioonites#afgi and in #aiji reinstated in ,nilssonia#afhj on the ground that the lamina covers the upper face of the rachis4 ,the segments are fairly uniform in breadth and linear2 they reach #aj cm4 in length and are usually #e-g mm4 broad2 the lamina is slightly tapered towards the apex 7fig4 #fai1 ,b74 ,there are #c-aj parallel grooves on the upper face of the segments and between each pair is a single unbranched vein4 ,in close association with portions of three fronds of this species ,nathorst found several oval bodies1 #a cm4 #g mm41 which he at first regarded as #8antherangia' comparable with the sporocarps of the ,hydropterideae1 but an examination of the carbonised tissue demonstrated that the small rounded bodies contained in each of the #8antherangia1' originally believed to be pollen-sacs1 are grains of resin internal to a cuticle of thick-walled cells and probably formed by secretory sacs in a fleshy tissue4 ,internal to the resin-bodies is a second cuticle which may be the remains of a nucellus1 the outer cuticle and the resin belonging to the sarcotesta4 ,nathorst's careful examination of these fossils shows that they are seeds 7fig4 #fai1 ,a7 and were probably borne on plants of ,n4 pterophylloides1 though an accidental association is not improbable4 ,nilssonia compta 7,phillips74 ,broadly linear fronds varying considerably in size and in the breadth and number of the truncate segments4 ,in some cases the fronds exceeded #dj cm4 in length and had a breadth of #i cm4 7fig4 #fbb74 ,the veins are simple1 parallel1 and fairly prominent and the lamina shows clearly the attachment to the upper surface of the rachis which is covered by it as in all species of the genus#afha4 ,the structure of the epidermis and stomata has recently been described by ,thomas#afhb4 ,brongniart mentioned in the ,prodrome a species from the ,lower ,oolite of ,yorkshire under the name ,pterophyllum ,williamsonis#afhc1 but in a later work this is given as a synonym of ,n4 compta4 ,nilssonia compta bears a close resemblance in habit to ,n4 polymorpha2 it agrees also with the large fronds described from the ,upper ,gondwana of ,india as ,pterophyllum princeps#afhd4 ,since attention was first called to this similarity an examination of several of the figured specimens has convinced me that the ,indian fronds are either identical with or at least closely allied to the ,european leaves4 ,the apparent lateral attachment of the lamina in the drawings published by ,oldham and ,morris and ,feistmantel is due to imperfect preservation2 the lamina ends in two raised ridges1 and the discovery of a specimen in which the lamina completely covers the rachis confirmed the impression made by the other specimens4 ,the ,amurland ,jurassic species ,nilssonia ,schmidtii#afhe ,heer though probably not identical with ,n4 compta is a very similar type2 it was originally described by ,heer as ,anomozamites ,schmidtii and transferred by ,nathorst#afhf to ,nilssonia3 the veins are occasionally forked near the rachis and are rather farther apart 7#e mm47 than in ,n4 compta and the segments are broader and deeper than in the ,english species4 ,nilssonia nipponensis ,yok4#afhg a ,jurassic species recorded from ,japan and ,north ,america is another similar type4 ,illustration3 ,fig4 #fbb4 ,nilssonia compta4 7,whitby ,museum2 nat4 size47 ,nilssonia orientalis ,heer4 ,in this ,jurassic and ,lower ,cretaceous species1 founded on material from ,jurassic rocks in ,siberia#afhh1 the lamina is generally entire4 ,the fronds exhibit a wide range in size and shape2 they may have the form of very narrow linear leaves barely #a cm4 across or may reach a breadth of nearly #aj cm4 ,the leaves from ,middle ,jurassic ,british strata named by ,nathorst ,n4 tenuinervis#afhi are probably identical with ,heer's type1 and ,n4 ,johnstrupi#afij ,heer from the ,lower ,cretaceous of ,greenland may also be referred to ,n4 orientalis4 ,the veins are at right-angles or oblique to the rachis and are very numerous1 three or more in a breadth of #a mm4#afia ,a species recently described by ,halle#afib from ,graham ,land as ,n4 taeniopteroides agrees closely in habit with ,n4 orientalis3 in the southern form the frond may have a length of #dj-ej cm4 and a breadth of #c cm4 ,the entire lamina of ,n4 taeniopteroides tapers gradually towards the base and is more rapidly narrowed in the distal region2 the petiole is at least #f-g cm4 long3 the simple or branched veins1 #ae-bj in #a cm41 are given off from the axis at a wide angle4 ,the more crowded veins in ,n4 orientalis constitute one of the few features in which it differs from ,halle's species1 but the fact that the degree of closeness of the veins is inconstant within the same species renders this distinction of doubtful value4 ,halle compares his species also with ,n4 densinervis 7,font47 originally described as ,platypterigium densinerve from the ,potomac beds#afic and afterwards transferred by ,berry#afid to ,nilssonia and considered by him to be identical with ,fontaine's ,platypterigium ,rogersianum4 ,an examination of some of ,fontaine's specimens in the ,washington ,museum led me to refer the fronds to ,nilssonia#afie4 ,it is impossible to speak with confidence as to the absolute specific identity of ,n4 orientalis ,heer1 ,n4 ,johnstrupi ,heer1 ,n4 taeniopteroides ,halle1 and some similar forms2 but it is clear that the linear fronds of this type characterised by an entire or occasionally pinnatisect lamina were widely distributed in ,jurassic and ,lower ,cretaceous strata and persisted to the ,upper ,cretaceous series in ,japan4 ,this form of frond is recorded from ,england1 ,scotland1 ,north ,america1 ,greenland1 ,spitzbergen#afif1 ,siberia1 ,russia1 ,afghanistan#afig1 ,japan#afih1 ,graham ,land1 and elsewhere4 ,reference has already been made to a petrified specimen of ,n4 orientalis described by ,dr ,stopes from ,japan#afii4 ,specimens described by ,salfeld#agjj from the ,corallian of ,germany as ,taeniopteris sp4 may be ,n4 orientalis2 ,bartholin's ,n4 polymorpha from ,bornholm1 ,velenovsk's ,lower ,cretaceous ,n4 bohemica and ,yokoyama's ,n4 ozvana from ,japan are other examples of fronds which may be identical with ,n4 orientalis#agja4 ,nilssonia tenuicaulis 7,phillips74 ,this ,jurassic species1 while agreeing generally in habit with ,n4 compta1 is characterised by the narrow and numerous linear segments with a more acuminate apex4 ,the fronds reached a length of more than #bj cm4#agjb ,leckenby's name ,pterophyllum medianum#agjc was given to a specimen from the ,yorkshire coast and now in the ,sedgwick ,museum1 ,cambridge1 which1 with ,pterophyllum angustifolium1 is clearly identical with ,cycadites tenuicaulis ,phillips4 ,the specific name mediana frequently used#agjd for this type should be given up in favour of the older term tenuicaulis4 ,a species of similar habit is described but not figured by ,krasser#agje as ,n4 ,sturii from the ,lunz beds4 ,n4 tenuicaulis is fairly common in the ,middle ,jurassic beds near ,scarborough and is recorded from the ,kimmeridgian of ,scotland under the name ,n4 mediana 7fig4 #fad1 ,c7#agjf4 ,nilssonia princeps 7,oldham and ,morris74 ,oldham and ,morris speak of ,pterophyllum princeps#agjg as one of the commonest plants in the ,rajmahal beds in ,india4 ,the fronds are characterised by their large size and by the very broad oblong and distally truncate pinnae with parallel and occasionally branched veins4 ,in the specimens figured by ,oldham and ,morris and ,feistmantel the pinnae are cut off at their bases 7fig4 #fbc71 which form ridges parallel to the rachis3 this feature is not clearly shown in the published drawings4 ,by breaking some pieces of rock from a slab containing figured specimens other pieces were found in which the laminae of the bases of segments meet in the middle of the upper face of the rachis4 ,the pinnae vary in breadth from #a cm4 to #ce cm4 and reach a length of #h cm42 the distal end is truncate1 the lower edge being strongly curved3 the segments are slightly broadened at the base4 ,the veins are prominent and parallel1 from #je to #jh mm4 apart4 ,the ,rajmahal fronds described as ,pterophyllum ,morrisianum#agjh appear to be indistinguishable from this species4 ,illustration3 ,fig4 #fbc4 ,nilssonia princeps4 7,slightly reduced2 ,indian ,geological ,survey1 ,calcutta47 ,nilssonia ,schaumburgensis 7,dunker74 ,this species1 first described as ,pterophyllum ,schaumburgense#agji from the ,wealden of ,germany1 affords a good illustration of a small type of frond closely resembling the much larger species ,n4 compta4 ,examples from ,english ,wealden rocks seldom exceed #a cm4 in breadth and are often much narrower2 the linear lamina is almost entire or divided into short and broad truncate segments of unequal breadth3 the veins are parallel and simple4 ,for figures of this species1 recorded from different ,european localities and from ,japan1 reference should be made to the accounts by ,schenk#agaj1 ,nathorst1 ,yokoyama1 ,yabe1 and ,fontaine4 ,,ctenis4 ,lindley and ,hutton4 ,the genus ,ctenis#agaa was founded on a piece of pinnate frond from the ,middle ,jurassic rocks of the ,yorkshire coast previously figured by ,phillips as ,cycadites sulcicaulis4 ,lindley and ,hutton regarded the plant as probably ,cycadean and proposed to apply the name ,ctenis to all leaves having the general characters of ,cycadeae1 but with #8the veins connected by forks or transverse bars4' ,while many authors have accepted ,ctenis as a ,cycadean genus1 by others#agab it has been placed among the ,ferns1 on the ground that some small circular elevations on the lamina of the segments of certain species are believed to be sori or sporangia4 ,since ,ettingshausen#agac and ,schenk#agad first noticed this feature ,raciborski#agae has figured several examples from ,poland and ,staub#agaf records similar circular bodies on a ,liassic ,hungarian species4 ,in no single instance have sporangia been found4 ,nathorst#agag proposed the designation ,anthrophyopsis 7because of the resemblance of the lamina in form and venation to the leaves of the ,fern ,anthrophyum7 for some ,rhaetic specimens from ,scania1 but as they were subsequently found to be segments of a pinnate frond he adopted the name ,ctenis4 ,an example in the ,manchester ,museum#agah 7fig4 #fbd7 from ,yorkshire1 mentioned by ,nathorst in an early paper as probably a new species of ,anthrophyopsis1 afforded good preparations of the cuticle 7fig4 #fbe7 which revealed the existence of circular elevations on the outer walls of the epidermal cells3 these may explain the nature of some at least of the supposed sporangia4 ,the walls of the epidermal cells are straight4 ,the name ,ctenis is applied to pinnate fronds which are probably ,cycadean though we have no evidence as to the nature of the stem or the reproductive organs4 ,ctenis fronds are among the largest ,cycadean leaves from ,mesozoic floras2 in ,ctenis hungarica ,staub the frond is said to have reached a length of #b met4 and in other species the dimensions exceed those of most pinnate leaves4 ,the stout rachis bears linear or broad-oblong pinnae attached at a wide angle and varying considerably in size and shape2 the pinnae are attached by the whole base which is usually broadened and decurrent but in a few cases slightly contracted 7e4g4 ,c4 ,zeyschneri ,rac4#agai74 ,for some fronds bearing broad and basally narrowed segments ,raciborski proposed the name ,ctenidiopsis in distinction from ,euctenis which he applies to the typical forms4 ,the pinnae may be long and narrow reaching a length of over #ab cm41 or short and broad3 in some cases the frond would be more correctly described as deeply pinnatisect2 the apex of the segments is acute1 bluntly rounded or truncate4 ,several veins pass into the base of each pinna and pursue a course approximately parallel to the edge of the lamina2 a characteristic feature is the occasional occurrence of oblique cross-connexions between the veins4 ,it is possible that in some species the pinnae had spinous margins as in the pinnae of uncertain affinity figured by ,fontaine#agbj as ,encephalartopsis nervosa from the ,potomac series4 ,our knowledge of the epidermal cells is very meagre3 in the specimen represented in fig4 #fbe the epidermal cells have straight walls and a central papilla4 ,the genus extends from ,triassic to ,upper ,jurassic rocks4 ,illustration3 ,fig4 #fbd4 ,ctenis sp4 ,single pinna4 7,manchester ,museum1 ,no4 #ec47 ,illustration3 ,fig4 #fbe4 ,ctenis sp4 ,the epidermis of the pinna shown in fig4 #fbd4 ,a1 surface-view2 p1 papillae2 s1 stomata4 ,b1 side-view4 7,manchester ,museum1 ,no4 #ec47 ,ctenis lunzensis ,stur4 ,this species1 first recorded by ,stur from the ,lunz ,upper ,triassic flora1 has recently been examined by ,krasser#agba and compared with the ,jurassic species ,ctenis sulcicaulis 7,phill47 7 ,c4 falcata ,lind4 and ,hutt47 and ,c4 ,potocki ,rac4 ,no figures or detailed descriptions have been published4 ,ctenis fallax ,nathorst4 ,this ,scanian ,rhaetic type#agbb1 including ,anthrophyopsis crassinervis1 ,a4 ,nilssoni1 and probably ,a4 obovata ,nath41 is characterised by very large obtusely pointed pinnae reaching at least #bj cm4 in length and over #c cm4 in breadth4 ,the veins are often #b mm4 apart and form long polygonal meshes4 ,nathorst figures small circular patches on the surface of the lamina4 ,raciborski#agbc1 on slender evidence1 refers a fragment from the ,jurassic of ,cracow to this species4 ,ctenis hungarica ,staub4 ,a species#agbd characterised by very large fronds reaching #b met41 bearing broad linear pinnae almost at right-angles and attached to the rachis by decurrent bases1 attaining a length of #ba cm4 and a breadth at the base of the lamina of #ce cm4 and #d cm4 a short distance from the acute apex4 ,the veins are parallel to the edge of the lamina1 but ,staub does not appear to have seen distinct anastomoses4 ,it is not improbable that ,staub's species may be identical with ,c4 asplenioides 7,ett47 from the ,lias of ,hungary1 specimens of which are preserved in the cole des ,mines1 ,paris4 ,ctenis asplenioides 7,ettingshausen74 ,this species was first described by ,ettingshausen#agbe from ,liassic strata in ,austria as ,taeniopteris asplenioides and compared by him to large simple fronds of ,asplenium nidus but distinguished by a deeply dissected lamina4 ,schenk#agbf found that the veins anastomose and adopted the name ,ctenis4 ,in habit very similar to ,c4 sulcicaulis1 but the pinnae are much broader1 exceeding #d cm41 and the veins are #c-e mm4 apart4 ,only the basal part of the segments is figured by ,ettingshausen4 ,specimens in the cole des ,mines1 ,paris1 from ,hungary have pinnae nearly #dj cm4 long and #be cm4 in breadth1 the parallel veins being connected by a few oblique branches4 ,both ,ettingshausen and ,schenk speak of small circular sori on the lower epidermis1 though these are not figured nor were any sporangia obtained4 ,this species and other examples of large ,ctenis fronds are described by ,raciborski from ,lower ,jurassic rocks in ,poland4 ,he figures part of a leaf of ,c4 ,zeyschneri#agbg #dj cm4 long bearing alternate pinnae approximately #aj cm4 long and nearly #d cm4 broad1 characterised by obtuse apices1 a decurrent lamina1 and anastomosing veins closer together 7#af-bd per #a cm47 than those of ,c4 asplenioides4 ,in one ,polish specimen1 ,c4 remotinervis#agbh1 with pinnae #e cm4 broad the lamina is represented in the upper part of the frond as continuous over the face of the rachis1 and--if the drawing is accurate--the frond in this respect differs from typical examples of ,ctenis and agrees with ,nilssonia4 ,a species of ,ctenis with broad pinnae is described by ,yokoyama#agbi from the ,jurassic of ,china as ,c4 ,kaneharai4 ,ctenis sulcicaulis 7,phillips74 ,this type#agcj is more familiar under the name ,ctenis falcata given to it by ,lindley#agca1 but if we follow ,lester ,ward#agcb in strict observance of the rule of priority1 a course from which ,i have frequently deviated on the ground of long usage1 the less familiar designation must be adopted4 ,fronds pinnate2 long and tapered linear pinnae sometimes exceeding #ab cm4 in length and #a cm4 in breadth attached obliquely or almost at right-angles to a fairly broad rachis 7fig4 #fbf74 ,the lamina is broadest at the base and the lower margin is strongly decurrent1 tapering distally to an acute apex4 ,the parallel and frequently anastomosing veins diverge slightly in the basal region of the pinnae4 ,though usually separate to the base1 the laminae of adjacent pinnae may be continuous as in a pinnatisect leaf#agcc4 ,this species is recorded also from ,north ,america1 and fronds of similar habit are figured by ,fontaine#agcd from the ,jurassic of ,oregon as ,ctenis orovillensis3 a fragment recorded from ,jurassic rocks in ,afghanistan as ,ctenis sp4 may belong to ,c4 sulcicaulis#agce4 ,ctenis latifolia 7,brongniart74 ,this species#agcf1 originally referred to ,taeniopteris1 was transferred to ,ctenis as the result of the discovery of anastomosing veins in the type-specimen in the ,oxford ,museum4 ,the segments are shorter and broader than in ,c4 sulcicaulis and very similar to those of ,c4 orovillensis ,font4 ,illustration3 ,fig4 #fbf4 ,ctenis sulcicaulis4 7,british ,museum1 ,v4 #ijab47 ,ctenis sp4 ,the pinna shown in fig4 #fbd from the ,jurassic beds in ,yorkshire#agcg is interesting as one of the few examples of the preservation of the cuticular membrane4 ,the straight or curved walls of the epidermal cells agree with those of recent ,cycads except ,stangeria1 and each cell bears a large central papilla that gives to the lamina the finely punctate appearance which has been regarded as evidence of sporangia4 ,the gaps in the cuticle probably mark the position of sunken stomata4 ,,pseudoctenis4 ,seward4 ,this genus#agch was established for certain pinnate fronds agreeing in habit with ,ctenis sulcicaulis but distinguished by the almost complete absence of any cross-connexions between the veins4 ,some of the forms with narrow pinnae closely resemble species of ,zamites1 the distinguishing feature being the decurrent lower margin of the leaflets4 ,though such fronds might not unreasonably be included in ,ctenis1 it is more convenient on the analogy of the occasional occurrence of ,glossopteris fronds with very few anastomoses to employ a distinctive designation4 ,illustration3 ,fig4 #fbg4 ,pseudoctenis eathiensis4 7,british ,museum1 ,no4 ,v4 #bgdd2 nat4 size47 ,pseudoctenis eathiensis 7,richards74 ,some of the specimens on which this species#agci is founded were originally figured by ,miller#agdj from ,upper ,jurassic strata in ,scotland and afterwards named by ,richards#agda ,zamites eathiensis4 ,the general appearance of the fronds is very like that of ,ctenis sulcicaulis2 the pinnae vary in breadth from about #c mm4 to #ae cm42 they are attached at right-angles or1 in the apical region1 may be almost parallel to the rachis4 ,the longest pinna recorded is #ag cm4 and the lamina tapers to a slender apex2 the veins are parallel and occasionally forked1 but cross-connexions are rare4 ,the partially petrified rachis of one specimen showed hypodermal stereome and some secretory canals as in recent ,cycads4 ,the specimen from ,wealden rocks near ,hastings 7fig4 #fbg71 originally described as ,zamites sp4#agdb1 is probably specifically identical with ,pseudoctenis eathiensis4 ,the ,south ,african ,wealden species1 originally described by ,tate as ,palaeozamia ,rubidgei#agdc1 agrees closely with ,pseudoctenis and is probably an example of that genus4 ,this type bears a close resemblance in the form of the frond to ,ctenophyllum grandifolium ,font4#agdd and ,c4 ,wardi#agde ,font4 from ,american ,trias and ,jurassic rocks respectively4 ,pseudoctenis crassinervis ,sew4#agdf is another ,scotch form with coarser veins4 ,a frond very similar in habit to ,p4 eathiensis is represented by ,pseudoctenis ensiformis ,halle#agdg from the ,jurassic strata of ,graham ,land originally referred by ,nathorst to ,pterophyllum4 ,an examination of the type-specimen in the ,stockholm ,museum revealed its resemblance to the ,scotch species ,p4 eathiensis3 a single anastomosis was noticed in one of the pinnae4 ,the broadly ensiform obtuse pinnae1 reaching a length of #g cm4 with a maximum breadth of #c cm4 at their expanded bases1 vary in breadth and are attached at right-angles to a slender rachis4 ,the veins1 #a-ae mm4 apart1 are parallel and strong4 ,the varying breadth of the pinnae irrespective of their position on the rachis is a distinctive feature4 ,halle draws attention to a resemblance of this ,antarctic species to ,ctenophyllum latifolium ,font4 a ,potomac type referred by ,berry#agdh to the genus ,ctenopsis on the rather slender ground that the veins are arranged in pairs4 ,berry in a footnote expresses the opinion that ,ctenopsis is very closely related to or possibly identical with ,pseudoctenis4 ,if the bases of the pinnae in the specimen of ,p4 ensiformis figured by ,halle are complete1 as they appear to be1 the frond agrees very closely with ,pterophyllum ,carterianum ,old4 and ,morr4#agdi from ,india4 ,a comparison of the ,rajmahal specimen with ,halle's figure leads me to regard the two fronds as probably identical4 ,the veins in the ,indian species1 which should also be referred to ,pseudoctenis1 are prominent and from #e to #a mm4 apart2 the base of the lamina is slightly broadened and the veins curve downwards towards the rachis in the lower decurrent portion4 ,the other ,indian type1 ,pterophyllum ,morrisianum#agej1 with which ,halle compares his species is1 however1 not a ,pseudoctenis but should be included in ,nilssonia and is probably identical with ,pterophyllum princeps ,old4 and ,morr4 ,pseudoctenis ,lanei ,thomas4 ,this species#agea1 recently described from ,middle ,jurassic beds at ,marske1 ,yorkshire1 has narrower linear lanceolate pinnae4 ,the linear pinnae reach a length of #aj cm4 and a breadth of #i mm4 ,the veins are numerous1 #aj in a breadth of #f mm41 and only one cross-vein was noticed4 ,in the decurrent lower edge of the laminae the fronds are identical with ,ctenis sulcicaulis4 ,a very good example of this species#ageb in the ,york ,museum is reproduced by ,mr ,thomas in his account of ,cleveland ,jurassic plants4 ,pseudoctenis ,balli 7,feistmantel74 ,a species described originally by ,feistmantel#agec as ,anomozamites ,balli from the ,barakar group of the ,damuda series and afterwards transferred to the genus ,platypterygium1 characterised by broadly linear segments of unequal breadth attached obliquely or at right-angles to a slender rachis4 ,the apices of the segments though usually imperfect appear to be truncate2 the bases of the pinnae are decurrent by their lower edge4 ,the veins are approximately #c per millimetre2 they are generally forked at the base and in one or two places show cross-connexions4 ,in the middle of the frond the narrow rachis is exposed but in the apical region it is covered by the laminae4 ,the occurrence of two divergent pinnae at the apex of the frond is a feature met with also in ,ctenis sulcicaulis4 ,this description is based on an examination of the specimens figured by ,feistmantel4 ,,iii4 ,cycadean ,fronds which cannot be assigned to a family-position4 ,,sphenozamites4 ,brongniart4 ,this name was proposed by ,brongniart#aged as a subgenus of ,otozamites denoting pinnate fronds bearing leaflets without an auriculate base3 he suggested that the subgenus might eventually be raised to generic rank and this was done by ,zigno#agee though in too wide a sense4 ,in the case of ,otozamites ,beani 7,lind4 and ,hutt471 quoted by ,brongniart in illustration of ,sphenozamites1 the latter designation is inapplicable as the pinnae are auriculate4 ,another species1 ,zamites undulatus ,sternb41 to which ,brongniart applied his new subgeneric term1 is probably identical with ,otozamites acuminatus 7,l4 and ,h47#agef4 ,although the distinction between ,sphenozamites and ,otozamites is often ill defined the former name may be conveniently adopted for pinnate fronds similar to those of ,zamia ,skinneri and some species of ,encephalartos characterised by leaflets of an asymmetrical1 obovate1 or rhomboidal form with a contracted or cuneate base and numerous branched divergent veins4 ,nothing is known of the structure or reproductive organs of ,sphenozamites1 and the genus1 though serving a useful descriptive purpose1 is founded solely on form1 and in the absence of other data it would be rash to assume that its use implies close natural affinity4 ,in the case of many other genera of ,cycadean fronds there is additional evidence of relationship1 but this is not the case with ,sphenozamites4 ,the pinnae resemble those of such recent ,cycadean fronds as ,zamia ,skinneri and ,z4 muricata4 ,the genus ranges from ,lower ,permian to ,jurassic rocks4 ,sphenozamites ,rochei ,renault4 ,this species#ageg1 from the ,lower ,permian of the ,autun district1 is founded on a pinnate frond bearing alternate pinnae1 #be #a cm41 with an asymmetrical oblong lamina attached obliquely near the edge of the rachis with a cuneate base slightly decurrent below and a broadly rounded apex2 the veins dichotomise once or twice as they diverge from the narrow base 7fig4 #fbh74 ,the pinnae resemble the leaflets of ,noeggerathia foliosa ,sternb4 and are similar in shape to those of the ,jurassic species ,sphenozamites ,geylerianus ,zig4 ,illustration3 ,fig4 #fbh4 ,sphenozamites ,rochei4 7,after ,renault2 nat4 size47 ,illustration3 ,fig4 #fbi4 ,sphenozamites ,belli4 7,oxford ,museum2 nat4 size47 ,sphenozamites ,belli ,seward4 ,this ,middle ,jurassic species from ,stonesfield#ageh is founded on detached pinnae possibly identical with a specimen figured by ,buckman as 8,naiadea obtusa#agei4 ,the pinnae are wedge-shaped1 tapering gradually to an acute apex and attached by a narrow base3 the leaflet shown in fig4 #fbi is #i cm4 long2 the veins are numerous and more divergent than in some leaves of similar form referred to the genus ,podozamites4 ,with this species may be compared several ,italian ,jurassic specimens described by ,zigno#agfj as four distinct species but more appropriately assigned to a single type ,s4 ,geylerianus4 ,an examination of ,zigno's fronds in the ,padua ,museum1 which he named ,s4 ,rossii1 leads me to regard the irregularly serrate edge of the pinnae as the result of tearing of an originally entire lamina and to compare the specimens with ,otozamites ,beani 7,l4 and ,h474 ,an imperfect ovoid pinna recalling ,s4 ,belli is figured by ,newberry from the ,rhaetic of ,honduras as ,sphenozamites robustus#agfa4 ,a ,french ,upper ,jurassic species figured by ,saporta as ,sphenozamites latifolius bears a very close resemblance in the form of the leaflets to the ,wealden plant ,sewardia latifolia#agfb4 ,kurtz records the occurrence of ,sphenozamites1 ,s4 ,geinitzianus1 from ,rhaetic strata in ,argentina#agfc1 but ,i have not seen any figures of this species4 ,,plagiozamites4 ,zeiller4 ,the name ,plagiozamites was proposed by ,zeiller#agfd for some pinnate fronds and detached leaflets from the ,stephanian of ,commentry and the ,lower ,permian of the ,vosges4 ,the better preservation of the ,vosges material enabled him to recognise certain features which led to the substitution of ,plagiozamites for ,zamites1 the name originally employed by ,renault for the ,commentry specimens4 ,plagiozamites bears a superficial resemblance to ,zamites and ,otozamites and differs but little from ,sphenozamites and ,noeggerathia2 it stands for pinnate fronds bearing ovate pinnae with a sub-amplexicaul oblique attachment to the rachis as is clearly shown in the species ,p4 ,planchardi 7,ren47#agfe4 ,in the case of ,palaeozoic fronds assigned to the ,cycadophyta on the ground of the resemblance of their pinnae to those of undoubted ,cycadean species1 it is particularly important to recognise the fact that decisive evidence as to systematic position is lacking4 ,we know nothing of the stem1 the reproductive organs1 or the epidermal and stomatal characters of ,plagiozamites1 and it is by no means certain that the genus is a true representative of the group in which it is provisionally included4 ,plagiozamites ,planchardi 7,renault74 ,fronds pinnate2 pinnae ovate-lanceolate reaching #e cm4 in length and #af cm4 in breadth1 inserted obliquely on the rachis1 but not along a line parallel to the long axis of the rachis as in ,zamites1 and partially embracing it3 the edge of the lamina is finely denticulate2 veins slightly divergent and occasionally branched4 ,the leaflets are narrow and more acute than those of ,noeggerathia and ,sphenozamites ,rochei ,ren4 ,plagiozamites is recorded from the ,stephanian of ,commentry1 the ,coal ,measures of ,manchuria#agff1 and the ,lower ,permian of the ,vosges4 ,renault described six species of ,zamites from ,commentry all1 except ,z4 carbonarius1 based on detached pinnae4 ,the type-specimen of ,z4 carbonarius consists of a piece of stout rachis bearing ovate acute pinnae1 #bb #a cm4 ,potoni#agfg1 who refers a piece of pinnate frond from the ,permian of ,thuringia to ,z4 carbonarius1 includes the other species of ,renault under that name4 ,whether or not the differences in the venation and form of the pinnae are of specific significance cannot be definitely settled without better material1 but the important point is that these ,permo-,carboniferous fronds are sufficiently distinct from ,zamites to be placed in a separate genus4 ,plagiozamites carbonarius is recorded also by ,zalessky#agfh from the ,permian of ,manchuria though the examples figured do not afford satisfactory evidence of the mode of insertion of the segments on the rachis4 ,p4 ,planchardi has recently been recorded from the ,coal ,measures of ,maryland2 the discovery is interesting both on phytogeographical grounds and as the first satisfactory record of a ,palaeozoic ,cycadophyte from ,north ,america#agfi4 ,cycadorachis4 ,saporta4 ,the employment of this generic name may serve a useful purpose if used for specimens1 whether preserved as petrifactions or impressions1 believed to be portions of ,cycadean frond-axes1 but which in the absence of pinnae cannot be assigned to one of the recognised genera of fronds4 ,saporta#aggj describes two species from ,kimmeridgian beds in ,france1 ,cycadorachis abscissa and ,c4 armata3 the first may be the winged base of a ,cycadean petiole1 but it agrees equally well with the broad base of an ,osmundaceous leaf and should not be referred to a genus implying affinity with a particular class4 ,the other species1 ,c4 armata1 is probably a piece of a spinous axis like that of the ,wealden plant ,sewardia latifolia 7,sap474 ,a fragment figured by ,fliche and ,bleicher#agga from the ,jurassic of ,nancy as ,c4 tuberculata is another example of a fossil which cannot be referred with any certainty to the ,cycads4 ,dr ,stopes#aggb1 inadvertently overlooking the previous institution of ,cycadorachis1 has recently proposed the name ,cycadeorachis for pinnately branched rachises of ,cycadean fronds which1 #8while indicating the general character of the frond1 do not show the shape of the pinnae well enough to be associated with any of the many foliage-genera4' ,,list ,,of ,,works ,,referred ,,to ,,in ,,the ,,text 7,volumes ,,iii4 and ,,iv47 ,with a few exceptions this list does not include books and papers given in the ,bibliographies in volumes ,i4 and ,,ii4 ,the following are some of the ,bibliographies which students will find useful for additional references3--,geological ,literature added to the ,geological ,society's ,library1 published from time to time by the ,society2 ,prof4 ,zeiller's lists in the #8,revue ,gnrale de ,botanique' 7,paris72 lists given by ,arber in the #8,progressus ,rei ,botanicae' 7,leiden71 vol4 i4 ,heft i4 p4 #bah1 #aijg2 ,jongman's #8,die ,palaeobotanische ,literatur' 7,jena71 #aiaj-ac2 also the ,international ,catalogue of ,scientific ,literature 7,botany and ,geology74 ,for the ,literature dealing with ,cretaceous plants the student should refer to ,dr ,marie ,stopes' #8,cretaceous ,flora' i4 and ii4 7,british ,museum ,catalogues1 #aiac1 #aiae74 ,the dates of books published in parts given in the footnotes to this volume are as a rule those of the concluding part4 ,for the dates of separate parts of books relating to ,palaeozoic floras the student is referred to ,prof4 ,zeiller's valuable list at the end of the #8,flore ,fossile du ,bassin ,houiller de ,valenciennes4' ,useful bibliographies of the writings of ,saporta1 ,heer1 and ,ettingshausen have been compiled by ,zeiller 7#if71 ,malloizel and ,zeiller 7,n4,d471 and ,krasser 7#ig74 ,aase1 ,hannah ,c4 7#ae7 ,vascular anatomy of the megasporophylls of ,conifers4 ,botanical ,gazette1 vol4 lx4 p4 #bgg4 ,affourtit1 ,m4 ,f4 ,a4 and ,h4 ,c4 ,c4 ,la ,rivire4 7#ae7 ,on the ribbing of the seeds of ,ginkgo4 ,annals of ,botany1 vol4 xxix4 p4 #eia4 ,andersson1 ,j4 ,g4 7#aj7 ,die ,vernderungen des ,klimas seit dem ,maximum der letzten ,eiszeit4 7,collection of papers published by the ,int4 ,geol4 ,congress2 edited by ,j4 ,g4 ,andersson47 ,stockholm4 ,andrews1 ,e4 ,b4 7#ge7 ,descriptions of ,fossil ,plants from the ,coal ,measures of ,ohio4 ,geol4 ,surv4 ,ohio4 ,antevs1 ,e4 7#ad7 ,lepidopteris ,ottonis 7,gpp47 ,schimp4 and ,anthotithus ,zeilleri ,nath4 ,k4 ,svensk4 ,vetenskapsakad4 ,hand4 ,bd4 li4 ,no4 #g4 ---- 7#ad7 ,the ,swedish ,species of ,ptilozamites ,nath4 ,ibid4 ,bd4 li4 ,no4 #aj4 ,arber1 ,agnes4 7,see also ,robertson1 ,a47 7#aj7 ,on the structure of the ,palaeozoic seed ,mitrospermum compressum 7,will474 ,ann4 ,bot4 vol4 xxiv4 p4 #dia4 ---- 7#ad7 ,a note on ,trigonocarpus4 ,ibid4 vol4 xxviii4 p4 #aie4 ,arber1 ,e4 ,a4 ,newell4 7#jb7 ,notes on the ,binney collection of ,coal-,measure ,plants4 ,pt4 iii4 ,the type-specimens of ,lyginodendron oldhamium 7,binney74 ,proc4 ,camb4 ,phil4 ,soc4 vol4 xi4 pt4 iv4 p4 #bha4 ---- 7#jc7 ,on the roots of ,medullosa anglica4 ,ann4 ,bot4 vol4 xvii4 p4 #dbe4 ---- 7#jc7 ,discussion on ,dr ,kurtz's paper 7#aijc74 ,quart4 ,journ4 ,geol4 ,soc4 vol4 lix4 p4 #bf4 ---- 7#jd7 ,cupressinoxylon ,hookeri sp4 nov4 a large silicified tree from ,tasmania4 ,geol4 ,mag4 v1 vol4 i4 p4 #g4 ---- 7#je7 ,on some new species of ,lagenostoma1 a type of ,pteridospermous seed from the ,coal ,measures4 ,proc4 ,r4 ,soc4 vol4 lxxi4 ,b1 p4 #bde4 ---- 7#jg7 ,on ,triassic species of the genera ,zamites and ,pterophyllum1 types of fronds belonging to the ,cycadophyta4 ,trans4 ,linn4 ,soc4 vol4 vii4 pt4 vii4 p4 #aji4 ---- 7#jh7 ,on a new ,pteridosperm possessing the ,sphenopteris type of foliage4 ,ann4 ,bot4 vol4 xxii4 p4 #eg4 ---- 7#ji7 ,on the ,fossil ,plants of the ,waldershare and ,fredville series of the ,kent ,coalfield4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 lxv4 p4 #ba4 ---- 7#ji7 ,on the affinities of the ,triassic plant ,yuccites vogesiacus ,schimp4 and ,moug4 ,geol4 ,mag4 v1 vol4 vi4 p4 #aa4 ---- 7#ab7 ,on ,psygmophyllum majus sp4 nov4 from the ,lower ,carboniferous rocks of ,newfoundland1 together with a ,revision of the genus and ,remarks on its affinities4 ,trans4 ,linn4 ,soc4 vol4 vii4 p4 #cia4 ---- 7#ab7 ,fossil ,plants from the ,kent ,coalfield4 ,geol4 ,mag4 v1 vol4 ix4 p4 #ig4 ---- 7#ac7 ,a preliminary note on the ,fossil ,plants of the ,mount ,potts beds1 ,new ,zealand1 collected by ,mr ,d4 ,g4 ,lillie1 ,biologist to ,capt4 ,scott's ,antarctic ,expedition in the 8,terra ,nova40 ,proc4 ,r4 ,soc4 vol4 lxxxvi4 p4 #cdd4 ---- 7#ac7 ,the structure of ,dadoxylon ,kayi4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 lxix4 p4 #ded4 ---- 7#ad7 ,a ,revision of the ,seed impressions of the ,british ,coal ,measures4 ,ann4 ,bot4 vol4 xxviii4 p4 #ha4 ---- 7#ad7 ,on the ,fossil ,flora of the ,kent ,coalfield4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 lxx4 p4 #ed4 ,arber1 ,e4 ,a4 ,newell and ,j4 ,parkin4 7#jg7 ,on the origin of ,angiosperms4 ,journ4 ,linn4 ,soc4 vol4 xxxviii4 p4 #bi4 ---- 7#jh7 ,studies on the ,evolution of the ,angiosperms4 ,ann4 ,bot4 vol4 xxii4 p4 #dhi4 ,arnoldi1 ,w4 7#ja7 ,beitrge zur ,morphologie einiger ,gymnospermen4 ,bull4 ,nat4 ,moscow1 ,no4 #d1 #aijj4 ,bailey1 ,i4 ,w4 7#ji7 ,the structure of the wood in the ,pineae4 ,bot4 ,gaz4 vol4 xlviii4 p4 #dg4 ---- 7#aa7 ,a ,cretaceous ,pityoxylon with marginal tracheids4 ,ann4 ,bot4 vol4 xxv4 p4 #cae4 ,baily1 ,w4 ,h4 7#fi7 ,notice of ,plant-remains from ,beds interstratified with the ,basalts in the county of ,antrim4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 xxv4 p4 #ceg4 ,bain1 ,f4 and ,sir ,w4 ,dawson4 7#he7 ,notes on the ,geology and ,fossil ,flora of ,prince ,edward ,island4 ,canadian ,rec4 ,sci4 vol4 i4 7#ahhd-he7 p4 #aed4 ,baker1 ,r4 ,t4 and ,h4 ,c4 ,smith4 7#aj7 ,research of the ,pines on ,australia4 ,dpt4 ,public ,instruction1 ,tech4 ,educ4 ,ser4 ,no4 #af4 ,sydney4 ,bancroft1 ,nellie4 7#ac7 ,on some ,indian ,jurassic ,gymnosperms and ,rhexoxylon africanum1 a new ,medullosan stem4 ,trans4 ,linn4 ,soc4 vol4 viii4 pt4 ii4 p4 #fi4 ---- 7#ad7 ,pteridosperm ,anatomy and its relation to that of the ,cycads4 ,new ,phyt4 vol4 xiii4 p4 #da4 ,barber1 ,c4 ,a4 7#ib7 ,on the nature and development of the corky excrescences on stems of ,zanthoxylum4 ,ann4 ,bot4 vol4 vi4 p4 #aee4 ---- 7#ih7 ,cupressionoxylon vectense2 a fossil ,conifer from the ,lower ,greensand of ,shanklin1 in the ,isle of ,wight4 ,ann4 ,bot4 vol4 xii4 p4 #cbi4 ,bartholin1 ,c4 ,t4 7#id7 ,nogle i den bornholmske ,juraformation forekommende ,planteforsteninger4 ,bot4 ,tidskrift 7,copenhagen71 ,bd4 xix4 p4 #hg4 ,bartlett1 ,a4 ,w4 7#ac7 ,note on the occurrence of an abnormal bisporangiate strobilus of ,larix europaea ,,dc4 ,ann4 ,bot4 vol4 xxvii4 p4 #ege4 ,bassler1 ,h4 7#af7 ,a ,cycadophyte from the ,north ,american ,coal ,measures4 ,amer4 ,journ4 ,sci4 vol4 xlii4 p4 #ba4 ,bayer1 ,a4 7#jh7 ,zur ,deutung der weiblichen ,blten der ,cupressineen nebst ,bemerkungen ber ,cryptomeria4 ,beiheft ,bot4 ,cent4 ,bd4 xxiii4 ,abt4 i4 p4 #bg4 ,beissner1 ,l4 7#ia7 ,handbuch der ,nadelholzkunde4 ,berlin4 ,bennett1 ,j4 ,j4 and ,r4 ,brown4 7#eb7 ,plantae ,javanicae rariores4 ,london1 #ahch-eb4 ,benson1 ,margaret4 7#jh7 ,on the contents of the pollen-chamber of a specimen of ,lagenostoma ovoides4 ,bot4 ,gaz4 vol4 lv4 p4 #dji4 ---- 7#ab7 ,cordaites ,felicis1 sp4 nov41 a ,cordaitean leaf from the ,coal ,measures of ,england4 ,ann4 ,bot4 vol4 xxvi4 p4 #bjb4 ---- 7#ad7 ,sphaerostoma ovale 7,conostoma ovale et intermedianum1 ,williamson71 a ,lower ,carboniferous ovule from ,pettycur1 ,fifeshire1 ,scotland4 ,trans4 ,r4 ,soc4 ,edinburgh1 vol4 l4 pt4 i4 ,no4 i4 p4 #a4 ,benson1 ,m4 and ,e4 ,j4 ,welsford4 7#ji7 ,the morphology of the ovule and female flower of ,juglans regia and of a few allied genera4 ,ann4 ,bot4 vol4 xxiii4 p4 #fbc4 ,berger1 ,r4 7#dh7 ,de fructibus et seminibus ex formatione lithanthracum4 ,diss4 ,inaug4 ,vratislaviae4 ,bergeron1 ,j4 7#hd7 ,note sur les strobiles du ,walchia piniformis4 ,bull4 soc4 gol4 ,france #c1 ,tome xii4 p4 #ehc4 ,berridge1 ,e4 ,m4 7#aa7 ,on some points of resemblance between ,gnetalean and ,bennettitean seeds4 ,new ,phyt4 vol4 x4 p4 #adj4 ---- 7#ab7 ,the structure of the female strobilus in ,gnetum ,gnemon4 ,ann4 ,bot4 vol4 xxvi4 p4 #ihg4 ,berridge1 ,emily ,m4 and ,elizabeth ,sanday4 7#jg7 ,oogenesis and embryogeny in ,ephedra distachya4 ,new ,phyt4 vol4 vi4 p4 #abg4 ,berry1 ,e4 ,w4 7#jc7 ,the ,flora of the ,matawan ,formation4 ,bull4 ,new ,york ,bot4 ,gard4 vol4 iii4 ,no4 #i1 p4 #de4 ---- 7#je7 ,additions to the fossil ,flora from ,cliffwood4 ,bull4 ,torrey ,bot4 ,club1 vol4 xxxii4 p4 #dc4 ---- 7#jf7 ,contributions to the ,mesozoic ,flora of the ,atlantic ,coastal ,plain4 ,i4 ,ibid4 vol4 xxxiii4 p4 #cc4 ---- 7#jg7 ,coastal ,plain ,amber4 ,torreya1 vol4 vii4 p4 #d4 ---- 7#jg7 ,contributions to the ,pleistocene ,flora of ,north ,carolina4 ,journ4 ,geol4 vol4 xv4 ,no4 #d1 p4 #cch4 ---- 7#jh7 ,some ,araucarian remains from the ,atlantic ,coastal ,plain4 ,bull4 ,torrey ,bot4 ,club1 vol4 xxxv4 p4 #bdi4 ---- 7#jh7 ,a ,mid-,cretaceous species of ,torreya4 ,amer4 ,journ4 ,sci4 vol4 xxv4 p4 #chb4 ---- 7#ji7 ,a ,miocene ,flora from the ,virginian ,coastal ,plain4 ,journ4 ,geol4 vol4 xvii4 p4 #ai4 ---- 7#ji7 ,pleistocene ,swamp deposits in ,virginia4 ,amer4 ,nat4 vol4 xliii4 p4 #dcb4 ---- 7#aj7 ,a revision of the ,fossil ,plants of the genus ,nageiopsis of ,fontaine4 ,proc4 ,u4 ,s4 ,nat4 ,mus4 vol4 xxxviii4 p4 #ahe4 ---- 7#aj7 ,the epidermal characters of ,frenelopsis ramosissimus4 ,bot4 ,gaz4 vol4 l4 p4 #cje4 ---- 7#aj7 ,additions to the ,pleistocene ,flora of ,new ,jersey4 ,torreya1 vol4 x4 p4 #bfa4 ---- 7#aj7 ,contributions to the ,mesozoic ,flora of the ,atlantic ,coastal ,plain4 ,v4 ,north ,carolina4 ,bull4 ,torrey ,bot4 ,club1 vol4 xxxvii4 p4 #aha4 ---- 7#aa7 ,the ,lower ,cretaceous deposits of ,maryland4 7,berry1 ,clark1 and ,bibbin47 ,maryland ,geol4 ,surv4 ---- 7#aa7 ,a ,lower ,cretaceous species of ,schizaeaceae from ,eastern ,north ,america4 ,ann4 ,bot4 vol4 xxv4 p4 #aic4 ---- 7#aa7 ,the ,flora of the ,raritan ,formation4 ,geol4 ,surv4 ,new ,jersey1 ,bull4 #c4 ---- 7#aa7 ,a ,revision of several genera of ,gymnospermous plants from the ,potomac group in ,maryland and ,virginia4 ,proc4 ,u4 ,s4 ,nat4 ,mus4 vol4 xl4 p4 #bhi4 ---- 7#ab7 ,the age of the plant-bearing shales of the ,richmond coal-field4 ,amer4 ,journ4 ,sci4 vol4 xxxiv4 p4 #bbd4 ---- 7#ab7 ,notes on the genus ,widdringtonites4 ,bull4 ,torr4 ,bot4 ,club1 vol4 xxxix4 p4 #cda4 ---- 7#ab7 ,contributions to the ,mesozoic ,flora of the ,atlantic ,coastal ,plain4 ,,vii4 ,texas4 ,bull4 ,torrey ,bot4 ,club1 vol4 xxxix4 p4 #chg4 ---- 7#ab7 ,pleistocene plants from the ,blue ,ridge in ,virginia4 ,amer4 ,journ4 ,sci4 vol4 xxxiv4 p4 #bah4 ---- 7#ad7 ,the ,upper ,cretaceous and ,eocene floras of ,south ,carolina and ,georgia4 ,u4 ,s4 ,geol4 ,surv4 ,professional papers1 ,no4 #hd4 ---- 7#ae7 ,the ,mississippi ,river ,bluffs at ,columbus and ,hickman1 ,kentucky1 and their ,fossil ,flora4 ,proc4 ,u4 ,s4 ,nat4 ,mus4 vol4 xlviii4 p4 #bic4 ---- 7#af7 ,the ,geological history of ,gymnosperms4 ,the ,plant ,world1 vol4 xix4 p4 #bg4 ,bertrand1 ,c4 ,e4 7#gd7 ,anatomie compare des tiges et des feuilles chez les ,gntaces et les ,conifres4 ,ann4 ,sci4 nat4 v1 vol4 xx4 p4 #e4 ---- 7#hc7 ,note sur le genre ,vesquia1 ,taxine fossile du ,terrain ,aachnien de ,tournai4 ,bull4 soc4 bot4 ,france #c1 ,tome v4 p4 #bic4 ---- 7#hi7 ,les ,poroxylons vgtaux fossiles de l'poque houillire4 ,ann4 soc4 ,belg4 de ,microscopie1 ,tome xiii4 ,fasc4 i4 ---- 7#ih7 ,remarques sur la structure des grains de pollen de ,cordaites4 ,assoc4 ,fran4 pour l'avanc4 des ,sci4 ,nantes 7#ahih71 p4 #dcf4 ---- 7#jg7 ,les caractristiques du genre ,rhabdocarpus d'aprs les prparations de la collection ,b4 ,renault4 ,bull4 soc4 bot4 #d1 ,tome vii1 p4 #fed4 ---- 7#jg7 ,les caractristiques du genre ,diplotesta de ,brongniart4 ,bull4 soc4 bot4 ,france #d1 tome vii4 p4 #chh4 ---- 7#jg7 ,les caractristiques du genre ,leptocaryon de ,brongniart4 ,ibid4 p4 #deb4 ---- 7#jg7 ,les caractristiques du genre ,taxospermum de ,brongniart4 ,ibid4 p4 #bac4 ---- 7#jg7 ,remarques sur le ,taxospermum angulosum4 ,compt4 rend4 d'assoc4 ,fran4 pour l'avanc4 des sci4 7,reims1 #aijg71 p4 #daj4 ---- 7#jh7 ,les caractristiques du ,cycadinocarpus angustodunensis de ,b4 ,renault4 ,bull4 soc4 bot4 ,france #d1 tome viii4 p4 #cbf4 ---- 7#jh7 ,les caractristiques du genre ,cardiocarpus d'aprs les graines silicifies tudies par ,ad4 ,brongniart et ,b4 ,renault4 ,ibid4 p4 #cia4 ---- 7#jh7 ,la spcification des ,cardiocarpus de la collection ,b4 ,renault4 ,ibid4 p4 #ded4 ---- 7#ji7 ,sur le genre ,compsotesta de ,ad4 ,brongniart4 ,ann4 ,jard4 ,bot4 ,buit4 #b1 suppl4 #c4 ---- 7#aa7 ,le ,bourgeon femelle des ,cordaites4 ,nancy4 ,bertrand1 ,c4 ,e4 et ,b4 ,renault4 7#hb7 ,recherches sur les ,poroxylons4 ,arch4 bot4 du ,nord de la ,france1 vol4 ii4 p4 #bdc4 ,bertrand1 ,p4 7#jh7 ,sur les stipes de ,clepsydropsis4 ,compt4 ,rend41 ,nov4 #af1 #aijh4 ---- 7#aa7 ,structure des stipes d',asterochlaena laxa ,sterzel4 ,mm4 soc4 gol4 ,nord1 ,tome vii4 i4 ---- 7#ac7 ,les ,fructifications de ,neuroptrides recueillies dans le terrain houiller du ,nord de la ,france4 ,ann4 soc4 gol4 ,nord1 ,tome xlii4 p4 #aac4 ---- 7#ad7 tat actuel de nos ,connaissances sur les ,genres #8,cladoxylon' et #8,steloxylon4' ,compt4 ,rend4 de l'assoc4 fran4 pour l',avancement des ,sciences 7,havre1 #aiad71 p4 #ddf4 ,beust1 ,f4 7#he7 ,untersuchung ber fossile ,hlzer aus ,grnland4 ,neue ,denksch4 allgem4 ,schweiz4 ,ges4 gesammt4 ,naturwiss4 ,bd4 xxix4 ,binney1 ,e4 ,w4 7#ff7 ,on ,fossil wood in calcareous nodules found in the upper foot coal near ,oldham4 ,proc4 ,lit4 ,phil4 ,soc4 ,manchester1 vol4 v4 p4 #aac4 ,bleicher and ,fliche4 7#ib7 ,contribution l'tude des ,terrains ,tertiaires d',alsace4 ,bull4 soc4 gol4 ,france #c1 ,tome xx4 p4 #cge4 ,bodenbender1 ,w4 7#if7 ,beobachtungen ber ,devon- und ,gondwana-,schichten in der ,argentinischen ,republik4 ,zeitsch4 ,deutsch4 geol4 ,ges4 ,bd4 xlviii4 p4 #gdc4 ---- 7#jb7 ,contribucion al ,conocimiento de la ,precordillera de ,san ,juan de ,mendoza4 ,bot4 ,acad4 ,nac4 ,cienc4 ,cordoba1 vol4 xvii4 p4 #bjc4 ,boodle1 ,l4 ,a4 7#ae7 ,concrescent and solitary ,foliage-leaves in ,pinus4 ,new ,phyt4 vol4 xiv4 p4 #ai4 ,boodle1 ,l4 ,a4 and ,w4 ,c4 ,worsdell4 7#id7 ,on the comparative anatomy of the ,casuarineae1 with special reference to the ,gnetaceae and ,cupuliferae4 ,ann4 ,bot4 vol4 viii4 p4 #bca4 ,boulay4 7#gi7 ,recherches de palontologie vgtale dans le terrain houiller du ,nord de la ,france4 ,ann4 soc4 scient4 ,bruxelles1 ann4 iv4 pt4 #b1 #ahhj4 ---- 7#hg7 ,notice sur la ,flore tertiaire des environs de ,privas 7,ardiche74 ,bull4 soc4 bot4 ,france1 ,tome xxxiv4 p4 #bbg4 ---- 7#hh7 ,notice sur les ,plantes fossiles des grs tertiaires de ,saint-,saturnin 7,marne et ,loire74 ,journ4 ,bot4 ,ann4 #b1 p4 #iba4 ,bower1 ,f4 ,o4 7#ha7 ,on the germination and histology of the seedlings of ,welwitschia mirabilis4 ,quart4 ,journ4 ,micr4 soc4 vol4 xxi4 pp4 #ae1 #ega4 ---- 7#hb7 ,the germination and embryogeny of ,gnetum ,gnemon4 ,ibid4 vol4 xxii4 ,n4,s41 p4 #bgg4 ---- 7#hd7 ,on the structure of ,rhynchopetalum montanum4 ,journ4 ,lin4 ,soc4 vol4 xx4 p4 #ddj4 ---- 7#ab7 ,studies in the ,phylogeny of the ,filicales4 ,,ii4 ,lophosira1 and its relation to the ,cyatheoideae and other ,ferns4 ,ann4 ,bot4 vol4 xxvi4 p4 #bfi4 ,bowerbank1 ,j4 ,s4 7#dj7 ,history of the ,fossil fruits and seeds of the ,london ,clay4 ,london4 ,braun1 ,a4 7#ge7 ,die ,frage nach der ,gymnospermie der ,cycadeen4 ,monatsber4 ,k4 ,preuss4 ,akad4 ,wiss4 ,berlin1 p4 #bhi4 ---- 7#ge7 ,die ,diagnosen dreier im ,jahre #ahgc von ,g4 ,wallis in ,neu ,granada entdeckter ,cycadeen4 ,ibid4 p4 #cgf4 ,braun1 ,c4 ,f4 ,w4 7#dc7 ,beitrge zur ,petrefactenkunde ,bayreuth 7,graf zu ,mnster71 ,heft vi4 ,bayreuth4 ---- 7#dg7 ,die ,fossile ,gewchse aus den ,grenzschichten zwischen dem ,lias und ,keuper des neu aufgefundenen ,pflanzenlagers in dem ,steinbrche von ,veitlahm bei ,culmbach4 ,flora1 p4 #ha4 ---- 7#di7 ,beitrge zur ,urgeschichte der ,pflanzen4 ,,vi4 ,weltrichia eine neue ,gattung fossiler ,rhizantheen4 ,progr4 iii4 ,jahresber4 ,k4 ,kreis-,landwirthsch4 und ,gewerbschule zu ,bayreuth4 ,brauns1 ,d4 7#ff7 ,der ,sandstein bei ,seinstedt unweit des ,fallsteins und die in ihm vorkommenden ,pflanzenreste4 ,paleont4 ,bd4 ix4 p4 #dg4 ,brenchley1 ,winifred ,e4 7#ac7 ,on ,branching specimens of ,lyginodendron ,oldhamium ,will4 ,journ4 ,linn4 ,soc4 vol4 xli4 p4 #cdi4 ,bristow1 ,h4 ,w4 7#fb7 ,the ,geology of the ,isle of ,wight4 ,mem4 ,geol4 ,surv4 ,great ,britain4 ,brongniart1 ,a4 7#be7 ,observations sur les vgtaux fossiles renferms dans les grs de ,hoer en ,scanie4 ,ann4 ,sci4 nat4 vol4 iv4 p4 #bjj4 ---- 7#bh7 ,essai d'une ,flore du grs bigarr4 ,ann4 ,sci4 nat4 vol4 v4 p4 #dce4 ---- 7#cc7 ,notice sur une ,conifre fossile du terrain d'eau douce de l'le d',iliodroma4 ,ann4 ,sci4 nat4 tome xxx4 p4 #age4 ---- 7#gd7 tudes sur les graines fossiles trouves l'tat silicifi dans le terrain ,houiller de ,saint tienne4 ,ann4 ,sci4 nat4 tome xx4 #e1 p4 #bcd4 ---- 7#ha7 ,recherches sur les graines fossiles silicifies4 ,paris4 ,bronn1 ,h4 ,g4 7#eh7 ,beitrge zur triassischen ,schiefer von ,raibl4 ,neues ,jahrb4 ,min4 p4 #abi4 ,brooks1 ,f4 ,t4 and ,a4 ,sharples4 7#ad7 ,pink disease4 ,bull4 ,no4 #ba1 ,depart4 ,agric4 ,fed4 ,malay ,states4 ,brooks1 ,f4 ,t4 and ,w4 ,stiles4 7#aj7 ,the structure of ,podocarpus spinulosus 7,smith7 ,r4 ,br4 ,ann4 ,bot4 vol4 xxiv4 p4 #cje4 ,buchman1 ,j4 7#de7 ,outline of the ,geology of the neighbourhood of ,cheltenham 7in collaboration with ,r4 ,i4 ,murchison and ,h4 ,e4 ,strickland74 ,london4 ,buckland1 ,w4 7#bh7 ,on the ,cycadeoideae1 a ,family of ,fossil ,plants found in the ,oolite quarries of the ,isle of ,portland4 ,trans4 ,geol4 ,soc4 #b1 vol4 ii4 p4 #cie4 ---- 7#cg7 ,geology and ,mineralogy considered with reference to ,natural ,theology4 ,london4 ,burckhardt1 ,c4 7#aa7 ,bemerkungen zu einigen ,arbeiten von ,w4 ,gothan und ,a4 ,g4 ,nathorst4 ,cent4 ,min4 ,geol42 ,paleont4 p4 #ddb4 ,burgestein1 ,a4 7#jf7 ,zur ,holzanatomie der ,tanne1 ,fichte und ,lrche4 ,ber4 deutsch4 ,bot4 ,ges4 ,bd4 xxiv4 ,heft vi4 p4 #bie4 ---- 7#jh7 ,vergleichende ,anatomie des ,holzes der ,koniferen4 ,wiesner-,festschrift1 ,wien4 ,burlingame1 ,l4 7#jh7 ,the staminate cone and male gametophyte of ,podocarpus4 ,bot4 ,gaz4 vol4 xlvi4 p4 #afa4 ---- 7#ac7 ,the ,morphology of ,araucaria brasiliensis4 ,bot4 ,gaz4 vol4 lv4 p4 #ig4 ---- 7#ae7 ,the ,morphology of ,araucaria brasiliensis4 ,ibid4 vol4 lix4 p4 #a4 ---- 7#ae7 ,the ,origin and ,relationships of the ,araucarians4 ,ibid4 vol4 lx4 p4 #a4 ,butterworth1 ,j4 7#ig7 ,some further investigations of ,fossil seeds of the genus ,lagenostoma 7,williamson7 from the ,lower ,coal ,measures1 ,oldham4 ,mem4 ,proc4 ,manchester ,lit4 and ,phil4 ,soc4 vol4 xli4 ix4 p4 #a4 ,caldwell1 ,o4 ,w4 7#jg7 ,microcycas calocoma4 ,bot4 ,gaz4 vol4 xliv4 p4 #aah4 ,caldwell1 ,o4 ,w4 and ,c4 ,f4 ,baker4 7#jg7 ,the identity of ,microcycas calocoma4 ,ibid4 vol4 xliii4 p4 #acj4 ,cambier1 ,r4 et ,a4 ,renier4 7#aj7 ,psygmophyllum ,delvali n4 sp4 du ,terrain houiller de ,charleroi4 ,ann4 soc4 gol4 ,belg4 ,tome ii4 p4 #bc4 7,mm4 in #dto47 ,capellini1 ,g4 and ,conte ,e4 ,solms-,laubach4 7#ib7 ,i ,tronchi di ,bennettitee dei ,musei ,italiani4 ,mem4 ,reale ,acad4 ,sci4 ,istit4 ,bologna #e1 tom4 ii4 p4 #afa4 ,carano1 ,e4 7#jd7 ,contribuzione alla conoscenza della ,morfologia e dello sviluppo del fascio vascolare delle foglie delle ,cicadacee4 ,ann4 di ,bot4 vol4 i4 p4 #aji 7,rome74 ,carpentier1 ,a4 7#aa7 ,sur quelques fructifications et inflorescences du ,westphalien du ,nord de la ,france4 ,rev4 ,gn4 ,bot4 tome xxiii4 p4 #a4 ---- 7#ac7 ,contribution l'tude du ,carbonifre du ,nord de la ,france4 ,mm4 soc4 gol4 du ,nord1 tome vii4 ii4 p4 #a4 ,carruthers1 ,w4 7#ff7 ,on ,araucarian cones from the ,secondary beds of ,britain4 ,geol4 ,mag4 vol4 iii4 p4 #bdi4 ---- 7#ff7 ,on some fossil ,coniferous fruits4 ,ibid4 vol4 iii4 p4 #ecd4 ---- 7#fg7 ,on ,cycadeoidea ,yatesii sp4 nov4 a fossil ,cycadean stem from the ,potton sands1 ,bedfordshire4 ,ibid4 vol4 iv4 p4 #aii4 ---- 7#fg7 ,on ,gymnospermous ,fruits from the ,secondary rocks of ,britain4 ,journ4 ,bot4 vol4 v4 p4 #a4 ---- 7#fg7 ,on some ,cycadean ,fruits from the ,secondary rocks of ,britain4 ,geol4 ,mag4 vol4 iv4 p4 #aja4 ---- 7#fh7 ,british ,fossil ,pandanaceae4 ,ibid4 vol4 v4 p4 #aec4 ---- 7#fi7 ,on ,beania1 a new genus of ,cycadean ,fruit from the ,yorkshire ,oolite4 ,ibid4 vol4 vi4 p4 #a4 ---- 7#fi7 ,on some undescribed ,coniferous fruits from the ,secondary rocks of ,britain4 ,ibid4 vol4 vi4 p4 #a4 ---- 7#gj7 ,on ,fossil ,cycadean stems from the ,secondary rocks of ,britain4 ,trans4 ,linn4 ,soc4 vol4 xxvi4 p4 #fge4 ---- 7#ga7 ,on two undescribed ,coniferous fruits from the ,secondary rocks of ,britain4 ,geol4 ,mag4 vol4 viii4 p4 #a4 ---- 7#gg7 ,description of a new species of ,araucarites from the ,coralline ,oolite of ,malton4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 xxxiii4 p4 #djb4 ---- 7#ic7 ,on ,cycas ,taiwaniana1 sp4 nov4 and ,c4 ,seemanni ,r4 ,br4 ,journ4 ,bot4 vol4 xxxi4 p4 #a4 ,carter1 ,m4 ,geraldine4 7#aa7 ,a ,reconsideration of the origin of ,transfusion-tissue4 ,ann4 ,bot4 vol4 xxv4 p4 #ige4 ,caspary1 ,r4 and ,r4 ,triebel4 7#hi7 ,einige fossile ,hlzer ,preussens4 ,k4 ,preuss4 ,geol4 ,landesanstalt1 ,bd4 ix4 ,heft iii4 p4 #aac4 elakovsk1 ,l4 7#hb7 ,zur ,kritik der ,ansichten von den ,fruchtschuppe der ,abietineen4 ,abh4 ,k4 bhm4 ,ges4 ,wiss4 ,prag vi1 ,bd4 ii4 ,chamberlain1 ,c4 ,j4 7#jf7 ,the ovule and female gametophyte of ,dioon4 ,bot4 ,gaz4 vol4 xlii4 p4 #cba4 ---- 7#ji7 ,dioon spinulosum4 ,ibid4 vol4 xlviii4 p4 #dja4 ---- 7#aj7 ,see ,coulter and ,chamberlain4 ---- 7#aj7 ,fertilization and embryogeny in ,dioon edule4 ,bot4 ,gaz4 vol4 l4 p4 #dae4 ---- 7#aa7 ,the adult ,cycad ,trunk4 ,ibid4 vol4 lii4 p4 #ha4 ---- 7#ab7 ,morphology of ,ceratozamia4 ,ibid4 vol4 liii4 p4 #a4 ---- 7#ab7 ,a round-the-world ,botanical ,excursion4 ,pop4 ,sci4 ,monthly1 vol4 lxxxi4 p4 #dag4 ---- 7#ab7 ,two species of ,bowenia4 ,bot4 ,gaz4 vol4 liv4 p4 #dai4 ---- 7#ac7 ,macrozamia ,moorei1 a connecting link between living and fossil ,cycads4 ,bot4 ,gaz4 vol4 lv4 p4 #ada4 ,chapman1 ,f4 7#ji7 ,jurassic ,plant-remains from ,gippsland1 ,pt4 ii4 ,rec4 ,geol4 ,surv4 ,victoria1 vol4 iii4 pt4 i4 p4 #ajc4 ,chrysler1 ,m4 ,a4 7#ae7 ,the ,medullary rays of ,cedrus4 ,bot4 ,gaz4 vol4 lix4 p4 #chg4 ,church1 ,a4 ,h4 7#ad7 ,on the ,floral ,morphology of ,welwitschia mirabilis 7,hooker74 ,phil4 ,trans4 ,r4 ,soc4 vol4 #bje1 p4 #aae4 ,cockerell1 ,t4 ,d4 ,a4 7#jf7 ,the ,fossil ,flora and ,fauna of the ,florissant 7,colorado7 shales4 ,univ4 ,colorado ,series1 vol4 iii4 ,no4 #c4 ---- 7#jh7 ,description of ,tertiary ,plants4 ,,ii4 ,amer4 ,journ4 ,sci4 vol4 xxvi #d1 p4 #ecg4 ---- 7#jh74 ,the ,fossil ,flora of ,florissant1 ,colorado4 ,bull4 ,amer4 ,mus4 ,nat4 ,hist4 vol4 xxiv4 p4 #ga4 ---- 7#jh7 ,florissant2 a ,miocene ,pompeii4 ,pop4 ,sci4 ,monthly 7,aug4 #aijh1 p4 #aab74 ,coemans1 ,e4 7#ff7 ,description de la flore fossile du premier tage du terrain ,crtac du ,hainaut4 ,mm4 ,acad4 ,r4 ,belg41 tome xxxvi4 ,coker1 ,w4 ,c4 7#jc7 ,on the gametophyte and embryo of ,taxodium4 ,bot4 ,gaz4 vol4 xxxvi4 p4 #a4 ---- 7#ji7 ,vitality of ,pine seeds and the delayed opening of cones4 ,amer4 ,nat4 vol4 xliii4 p4 #fgg4 ,compter1 ,g4 7#id7 ,die fossile ,flora des untern ,keupers von ,ostthringen4 ,zeitsch4 fr ,naturwiss4 ,leipzig1 ,bd4 lxvii4 p4 #bje4 ---- 7#jc7 ,cycadeenfrchte aus der ,lettenkohle von ,apolda4 ,zeitsch4 fr ,naturwiss4 ,stuttgart1 ,bd4 lxxv4 p4 #aga4 ,compton1 ,r4 ,h4 7#jh7 ,see ,south and ,compton4 ,cowentz1 ,h4 7#gh7 ,ueber ein tertiares ,vorkommen ,cypressenartiger ,hlzer bei ,calistoga in ,californien4 ,neues ,jahrb4 ,min4 p4 #hjj4 ---- 7#hb7 ,fossile ,hlzer aus der ,sammlung der ,knig4 geol4 ,landesanstalt zu ,berlin4 ,jahrb4 ,k4 preuss4 geol4 ,land4 ,bergakad4 ,berlin fr das ,jahr #ahha1 p4 #add4 ---- 7#he7 ,sobre algunos arboles fosiles del ,rio ,negro4 ,bol4 ,acad4 ,nac4 ,cienc4 ,cordoba1 tom4 vii4 p4 #ege4 ---- 7#hf7 ,die ,angiospermen des ,bernsteins4 ,danzig4 ---- 7#hi7 ,ueber ,thyllen und ,thyllen-hnliche ,bildungen1 vornehmlich im ,hlze der ,bernsteinbume4 ,ber4 ,deutsch4 ,bot4 ,ges4 ,bd4 vii4 p4 7#cd74 ---- 7#ib7 ,untersuchungen ber fossile ,hlzer ,schwedens4 ,k4 ,svensk4 ,vetenskapsakad4 ,hand4 ,bd4 xxiv4 ,no4 #ac4 ---- 7#ja7 ,the past history of the ,yew in ,great ,britain and ,ireland4 ,rep4 #gast ,meeting ,brit4 ,assoc4 7,glasgow71 p4 #hci4 ,coulter1 ,j4 ,m4 and ,c4 ,j4 ,chamberlain4 7#jc7 ,the ,embryogeny of ,zamia4 ,bot4 ,gaz4 vol4 xxxv4 p4 #ahd4 ---- 7#aj7 ,morphology of ,gymnosperms4 ,chicago4 ,cramer1 ,c4 7#fh7 ,fossile ,hlzer der ,arctischen ,zone4 ,heer's ,foss4 ,flor4 ,arct4 vol4 i4 p4 #afg4 ,cri1 ,l4 7#hi7 ,beitrge zur ,kenntniss der fossilen ,flora einiger ,inseln des ,sdpacifischen und ,indischen ,oceans4 ,pal4 ,abhand4 7,dames and ,kayser7 7,n4,f471 ,bd4 i4 ,heft ii4 ,daguillon1 ,a4 7#ij7 ,recherches morphologiques sur les feuilles des ,conifres4 ,rev4 ,gn4 ,bot4 tome #aa1 p4 #aed4 ,dawson1 ,j4 ,w4 7#df7 ,notices of some ,fossils found in the ,coal ,formation of ,nova ,scotia4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ii4 p4 #acb4 ---- 7#fb7 ,on the ,flora of the ,devonian period in ,north-eastern ,america4 ,ibid4 vol4 xviii4 p4 #bif4 ---- 7#fc7 ,further ,observations on the ,devonian ,plants of ,maine1 ,gasp1 and ,new ,york4 ,ibid4 vol4 xix4 p4 #deh4 ---- 7#fc7 ,synopsis of the ,flora of the ,carboniferous ,period in ,nova ,scotia4 ,the ,canadian ,nat4 and ,geologist1 vol4 viii4 p4 #dca4 ---- 7#ha7 ,notes on ,new ,erian 7,devonian7 plants4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 xxxvii4 p4 #bii4 ---- 7#he7 ,on the ,mesozoic ,floras of the ,rocky ,mountains ,region of ,canada4 ,trans4 ,r4 ,soc4 ,canada1 sect4 iv4 p4 #a4 ---- 7#ij7 ,on new plants from the ,erian and ,carboniferous1 and on the characters and affinities of ,palaeozoic ,gymnosperms4 ,canadian ,rec4 ,sci4 vol4 iv4 p4 #a4 ---- 7#ic7 ,on new species of ,cretaceous plants from ,vancouver ,island4 ,trans4 ,r4 ,soc4 ,canada1 sect4 iv4 p4 #ec4 ,dawson1 ,sir ,j4 ,w4 and ,d4 ,p4 ,penhallow4 7#ia7 ,note on the specimens of ,fossil wood from the ,erian 7,devonian7 of ,new ,york and ,kentucky4 ,the ,canadian ,rec4 ,sci4 vol4 iv4 p4 #bdb4 ,depape1 ,g4 7#ac7 ,sur la prsence du ,ginkgo biloba ,l4 dans le ,pliocne infrieur de ,saint-,marcel-d',ardche4 ,compt4 ,rend4 vol4 #aeg1 p4 #ieg4 ,depape1 ,g4 and ,a4 ,carpentier4 7#ac7 ,prsence des genus ,gnetopsis ,b4 ,ren4 and ,r4 ,zeill4 et ,urnatopteris ,kidst4 dans le ,westphalien du ,nord de la ,france4 ,ann4 soc4 gol4 du ,nord1 tome xlii4 p4 #bid4 ---- 7#ae7 ,sur quelques graines et fructifications du ,westphalien du ,nord de la ,france4 ,rev4 ,gn4 ,bot4 vol4 xxvii4 p4 #cba4 ,dorety1 ,helen ,a4 7#jh7 ,the embryo of ,ceratozamia1 a physiological study4 ,bot4 ,gaz4 vol4 xlv4 p4 #dab4 ---- 7#jh7 ,the seedling of ,ceratozamia4 ,ibid4 vol4 xlvi4 p4 #bje4 ---- 7#ji7 ,the extrafascicular cambium of ,ceratozamia4 ,ibid4 vol4 xlvii4 p4 #adi4 ---- 7#ji7 ,vascular anatomy of the seedling of ,microcycas ,calocoma4 ,ibid4 p4 #aci4 ,dorrien-,smith1 ,a4 ,a4 7#aa7 ,a ,botanizing expedition to ,west ,australia4 ,journ4 ,r4 ,hort4 ,soc4 vol4 xxxvi4 p4 #bhe4 ,douvill1 ,h4 et ,r4 ,zeiller4 7#jh7 ,sur le terrain houiller du ,sud ,oranais4 ,compt4 ,rend4 tome cxlvi4 p4 #gcb4 ,drude1 ,o4 7#ij7 ,handbuch der ,pflanzengeographie4 ,stuttgart4 ,dmmer1 ,r4 7#ab7 ,podocarpus formosensis4 ,gard4 ,chron4 ,oct4 #ai1 p4 #bie4 ,dun1 ,w4 ,s4 7#aj7 ,notes on some ,fossil plants from the roof of the coal seam in the ,sydney ,harbour ,colliery4 ,journ4 ,proc4 ,r4 ,soc4 ,new ,south ,wales1 vol4 xliv4 p4 #fae4 ,duns1 ,j4 7#gb7 ,on ,cardiocarpon4 ,proc4 ,r4 ,soc4 ,edinburgh1 p4 #fib4 ,dunek1 ,f4 7#ac7 ,spaltffnungen der ,cycadaceen4 7,abstract in the ,bot4 ,cent4 ,bd4 cxxv4 p4 #cdj47 ,dusn1 ,p4 7#ii7 ber die ,tertire ,flora der ,magellans-,lnder4 ,wiss4 ,ergeb4 ,schwed4 ,exped4 nach den ,magellanslndern unter ,leitung von ,o4 ,nordenskjld1 ,bd4 i4 ,no4 iv4 p4 #hg4 ---- 7#jh7 ber die ,tertire ,flora der ,seymour-,insel4 ,wiss4 ,ergeb4 ,schwed4 ,sdpolar-,exped4 #aija-jc1 ,bd4 iii4 ,lief4 iii4 p4 #a4 ,duthie1 ,augusta ,v4 7#ab7 ,anatomy of ,gnetum africanum4 ,ann4 ,bot4 vol4 xxvi4 p4 #eic4 ,eames1 ,a4 ,j4 7#ac7 ,the ,morphology of ,agathis australis4 ,ann4 ,bot4 vol4 xxvii4 p4 #a4 ,eberdt1 ,o4 7#id7 ,die ,braunkohlen ,ablagerungen in der ,gegend von ,senftenberg4 ,jahrb4 ,k4 ,preuss4 ,geol4 ,land4 ,bergakad4 ,berlin1 ,bd4 xiv4 p4 #bab4 ,eichler1 ,a4 ,w4 7#ha7 ber die weiblichen ,blthen der ,coniferen4 ,monatsber4 ,k4 ,akad4 ,wiss4 ,berlin1 p4 #ajbj4 ---- 7#hb7 ber ,bildungsabweichungen bei ,fichtenzapfen4 ,sitzber4 ,k4 ,akad4 ,wiss4 ,berlin1 p4 #dj4 ---- 7#hi7 ,gymnospermae4 ,engler and ,prantl2 ,die ,natrlichen ,pflanzenfamilien1 ,teil ii4 ,eichwald1 ,e4 7#ec-fh7 ,lethaea rossica4 ,stuttgart4 ,elkins1 ,marion ,g4 and ,g4 ,r4 ,wieland4 7#ad7 ,cordaitean wood from the ,indiana ,black ,shale4 ,amer4 ,journ4 ,sci4 vol4 xxxviii4 p4 #fe4 ,elwes1 ,h4 ,j4 7#ab7 ,the ,flora of ,formosa4 ,gard4 ,chron4 ,july #ac1 #aiab1 p4 #be4 ,elwes1 ,h4 ,j4 and ,a4 ,henry4 7#fj7 ,the trees of ,great ,britain and ,ireland1 vol4 i4 ,edinburgh4 ,endlicher1 ,s4 7#dj7 ,genera plantarum secundum ordines naturales disposita4 ,vindobonae1 #ahcf-dj4 ---- 7#dg7 ,synopsis ,coniferarum4 ,sangalli4 ,engelhardt1 ,h4 7#he7 ,die ,tertirflora des ,jesuitengrabens bei ,kundratitz in ,nordbhmen4 ,nov4 ,act4 ,k4 ,leop4-,car4 ,deutsch4 ,akad4 ,naturforsch4 ,bd4 xlviii4 ,no4 #c1 p4 #bii4 ---- 7#ia7 ber ,tertirpflanzen von ,chile4 ,abh4 ,senckenberg4 naturforsch4 ,ges4 p4 #fbi4 ---- 7#ab7 ,weiterer ,beitrag zur ,kenntniss der fossilen ,tertirflora ,bosniens4 ,wiss4 ,mitt4 aus ,bosnien und der ,herzegowina1 ,bd4 xii4 p4 #eic4 ,engelhardt1 ,h4 and ,f4 ,kinkelin4 7#jh7 ,oberpliocene ,flora und ,fauna des ,unter-,maintales4 ,abh4 ,senck4 ,naturforsch4 ,ges4 ,bd4 xxix4 ,heft iii4 p4 #aea4 ,engler1 ,a4 7#hi7 ,engler and ,prantl2 ,die ,natrlichen ,pflanzenfamilien1 ,teil ii4 ,abt4 i4 ---- 7#ie7 ,die ,pflanzenwelt st ,afrikas1 etc4 ,th4 ,c4 ,berlin4 ---- 7#ig7 ,engler and ,prantl2 ,die ,natrlichen ,pflanzenfamilien4 ,nachtrag zu ,teilen ii-iv4 ,essner1 ,b4 7#hf7 ,ueber den diagnostischen ,werth der ,anzahl und ,hhe der ,markstrahlen bei den ,coniferen4 ,abh4 naturforsch4 ,ges4 ,halle1 ,bd4 xvi4 p4 #a4 ,etheridge1 ,r4 7#ic7 ,on the occurrence of a plant allied to ,schizoneura in the ,hawkesbury ,sandstone4 ,rec4 ,geol4 ,surv4 ,new ,south ,wales1 vol4 iii4 pt4 iii1 p4 #gd4 ,ettingshausen1 ,c4 von4 7#ea7 ,ueber einige neue und interessante ,taeniopteris ,arten aus den ,sammlungen des ,kais4 ,hof ,mineralien ,cabinetes und der ,k4k4 geol4 ,reichsanstalt4 ,naturwiss4 ,abh4 ,w4 ,haidinger1 vol4 iv4 p4 #ie4 ---- 7#eb7 ,beitrag zur nheren ,kenntniss der ,flora der ,wealdenperiode4 ,abh4 ,k4k4 geol4 ,reichs4 ,wien1 ,bd4 i4 ,abth4 iii4 ,no4 #b1 p4 #a4 ---- 7#eb7 ,die ,steinkohlenflora von ,stradonitz4 ,ibid4 ,bd4 i4 ,abth4 iii4 ,no4 #d4 ---- 7#ee7 ,die ,tertire ,flora von ,hring in ,tirol4 ,ibid4 ,bd4 ii4 ,abth4 ii4 ,no4 #b4 ---- 7#eg7 ,die ,fossile ,flora von ,kflach in ,steiermark4 ,jahrb4 ,k4k4 geol4 ,reichs4 ,bd4 viii4 p4 #gch4 ---- 7#eh7 ,beitrge zur ,kenntniss der fossilen ,flora von ,sotzka in ,untersteiermark4 ,sitz4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 xxviii4 p4 #dga4 ---- 7#fg7 ,die ,kreideflora von ,niederschoena in ,sachsen4 ,ibid4 ,bd4 lv4 ,abth4 i4 p4 #bce4 ---- 7#fg7 ,die fossile ,flora des ,tertir-,beckens von ,bilin4 ,denksch4 ,wiss4 ,akad4 ,wien1 ,bd4 xxvi4 p4 #gi4 ---- 7#gj7 ,beitrag zur ,kenntniss der ,tertirflora ,steiermarks4 ,sitz4 ,k4 ,akad4 ,wien1 ,bd4 lx4 ,abth4 i4 p4 #ag4 ---- 7#gb7 ,die ,fossile ,flora von ,sagor in ,krain4 ,denksch4 ,wiss4 ,akad4 ,wien1 ,bd4 xxxii4 p4 #cb4 ---- 7#gh7 ,beitrag zur ,erforschung der ,phylogenie der ,pflanzenarten4 ,ibid4 ,bd4 xxxviii4 p4 #fe4 ---- 7#gi7 ,report on ,phyto-,palaeontological ,investigations of the ,fossil ,flora of ,sheppey4 ,proc4 ,r4 ,soc4 vol4 xxix4 p4 #chh4 ---- 7#hj7 ,report on ,phyto-,palaeontological ,investigations of the ,fossil ,flora of ,alum ,bay4 ,ibid4 vol4 xxx4 p4 #bbh4 ---- 7#he7 ,die ,fossile ,flora von ,sagor in ,krain4 ,denksch4 ,wiss4 ,akad4 ,wien1 ,bd4 l4 p4 #a4 ---- 7#hf7 ,beitrge zur ,kenntniss der ,tertirflora ,australiens4 ,ibid4 ,bd4 liii4 p4 #ha4 ---- 7#hg7 ,beitrge zur ,kenntniss der ,fossile ,flora ,neuseelands4 ,denksch4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 liii4 p4 #c4 ---- 7#hh7 ,contributions to the ,tertiary ,flora of ,australia4 ,mem4 geol4 ,surv4 ,n4,s4,w4 ,pal4 ,no4 #b4 ---- 7#hh7 ,die ,fossile ,flora von ,leoben in ,steiermark4 ,denksch4 ,k ,akad4 ,wiss4 ,wien1 ,bd4 liv4 ,abth4 i4 p4 #bfa4 ---- 7#ij7 ,die ,fossile ,flora von ,schoenegg bei ,wies in ,steiermark4 ,ibid4 ,bd4 lvii4 p4 #fa4 ,ewart1 ,a4 ,j4 7#jh7 ,on the longevity of seeds4 ,proc4 ,r4 ,soc4 ,victoria1 vol4 xxi4 7,n4,s471 pt4 i4 p4 #a4 ,feistmantel1 #j4 7#gb7 ,beitrag zur ,kenntniss der ,ausdehnung des sogennanten ,wyaner ,gasschiefers und seiner ,flora4 ,jahrb4 ,k4k4 geol4 ,reichs4 ,wien1 ,bd4 xxii4 p4 #bhi4 ---- 7#gf7 ,notes on the age of some ,fossil ,floras in ,india4 ,rec4 ,geol4 ,surv4 ,ind4 vol4 ix4 pt4 iv4 p4 #aae4 ---- 7#gf7 ,jurassic 7,oolitic7 ,flora of ,kach4 ,fossil ,flora of the ,gondwana ,system1 pt4 i4 vol4 ii4 #ahhj4 ---- 7#gg7 ,notes on ,fossil ,floras in ,india4 ,rec4 ,geol4 ,surv4 ,ind4 vol4 x4 pt4 iv4 p4 #aif4 ---- 7#gg7 ,jurassic 7,liassic7 ,flora of the ,rajmahal group in the ,rajmahal hills4 ,foss4 ,flor4 ,gond4 ,syst4 vol4 i4 pt4 ii4 ---- 7#gg7 ,jurassic 7,liassic7 ,flora of the ,rajmahal group from ,golapili1 near ,ellore1 ,s4 ,godaveri4 ,ibid4 pt4 iii4 ---- 7#gg7 ,flora of the ,jabalpur group 7,upper ,gondwanas7 in the ,son-,narbada region4 ,ibid4 vol4 ii4 pt4 ii4 ---- 7#gg7 ,ueber die ,gattung ,williamsonia ,carr4 in ,indien4 ,palaeontolog4 ,beit4 ,palaeontograph4 ,suppl4 iii4 ,lief4 iii4 ---- 7#gi7 ,upper ,gondwana ,flora of the outliers on the ,madras coast4 ,foss4 ,flor4 ,gond4 ,syst4 vol4 i4 pt4 iv4 ---- 7#gi7 ,the ,flora of the ,talchir-,karharbari beds4 ,ibid4 vol4 iii4 pt4 i4 ---- 7#hj7 ,the ,flora of the ,damuda-,panchet ,divisions4 ,ibid4 vol4 iii4 pt4 ii4 ---- 7#hj7 ,note on the fossil genera ,noeggerathia ,sternberg1 ,noeggerathiopsis ,feist4 and ,rhiptozamites ,schmal4 ,rec4 ,geol4 ,surv4 ,india1 vol4 xiii4 pt4 i4 p4 #fa4 ---- 7#hj7 ,further notes on the correlation of the ,gondwana ,flora with other ,floras4 ,rec4 ,geol4 ,surv4 ,ind4 vol4 xiii4 pt4 iii4 p4 #aij4 ---- 7#ha7 ,palaeontological notes from the ,hazribgh and ,lohrdagga ,districts4 ,ibid4 vol4 xiv4 pt4 iii4 p4 #bda4 ---- 7#ha7 ,the ,flora of the ,talchir-,karharbari beds4 ,foss4 ,flor4 ,gond4 ,syst4 vol4 iii4 pt4 i4 ---- 7#ha7 ,the ,flora of the ,damuda-,panchet ,divisions4 ,ibid4 vol4 iii4 pt4 iii4 ---- 7#hb7 ,the ,fossil ,flora of the ,south ,rewah ,gondwana ,basin4 ,ibid4 vol4 iv4 pt4 i4 ---- 7#hf7 ,the ,fossil ,flora of some of the ,coalfields in ,western ,bengal4 ,ibid4 vol4 iv4 pl4 ii4 ---- 7#hi7 bersichtliche ,darstellung der geologisch-palaeontologischer ,verhltnisse ,sd-,afrikas4 ,th4 i4 ,abh4 ,k4 bhm4 ,ges4 ,wiss4 vii1 ,bd4 iii4 ,felix1 ,j4 7#hb7 ,beitrge zur ,kenntniss fossiler ,coniferen-,hlzer4 ,engler's ,jahrb4 ,bd4 iii4 p4 #bfj4 ---- 7#hd7 ,die ,holzopale ,ungarns in ,palaeophytologischen ,hinsicht4 ,mitt4 ,jahrb4 ,k4 ,ung4 geol4 ,anst4 ,bd4 vii4 ---- 7#hg7 ,untersuchungen ber fossile ,hlzer4 ,zeitsch4 ,deutsch4 geol4 ,ges4 p4 #eag4 ---- 7#id7 ,untersuchungen ber fossile ,hlzer4 ,ibid4 ,heft i4 p4 #gi4 ---- 7#if7 ,untersuchungen ber fossile ,hlzer4 ,ibid4 ,heft ii4 p4 #bdi4 ,fiedler1 ,h4 7#eg7 ,die ,fossile ,frchte der ,steinkohlen-formation4 ,acad4 ,caes4 ,leop4 ,nov4 ,acta1 ,bd4 xxvi4 p4 #bci4 ,fliche1 ,p4 7#if7 tude sur la flore fossile de l',argonne 7,albien-,cenomanien74 ,bull4 soc4 sci4 ,nancy4 ---- 7#ig7 ,note sur les nodules et bois minraliss trouvs ,st ,parres-les-vaudes 7,aube7 dans les grs verts infracrtacs4 ,mem4 soc4 ,acad4 de l',aube1 tome lx4 ---- 7#ii7 ,note sur quelques fossiles vgtaux de l',oligocne dans les ,alpes ,franaises4 ,bull4 soc4 gol4 ,france #c1 tome xxvii4 p4 #dff4 ---- 7#jj7 ,contribution la ,flore fossile de la ,haute-,marne 7,infracrtace74 ,bull4 soc4 sci4 ,nancy4 ---- 7#jj7 ,note sur un bois fossile de ,madagascar4 ,bull4 soc4 gol4 ,france #c1 tome xxviii4 p4 #dgj4 ---- 7#jc7 ,note sur des bois silicifis ,permiens de la valle de ,celles 7,vosges74 ---- 7#je7 ,note sur des bois fossiles de ,madagascar4 ,bull4 soc4 gol4 ,france #d1 tome v1 p4 #cdf4 ---- 7#aj7 ,flore ,fossile du ,trias en ,lorraine et ,franche-,comt avec des considrations finales par ,m4 ,r4 ,zeiller4 ,paris4 ,fliche1 ,p4 and ,bleicher4 7#hb7 tude sur la flore de l'oolithe infrieure aux environs de ,nancy4 ,bull4 soc4 sci4 ,nancy4 ,fliche1 ,p4 and ,r4 ,zeiller4 7#jd7 ,note sur une florule ,portlandienne des environs de ,boulogne-sur-mer4 ,bull4 soc4 gol4 ,france #d1 tome iv1 p4 #ghg4 ,fontaine1 ,w4 ,m4 7#ic7 ,notes on some ,fossil plants from the ,trinity ,division of the ,comanche series of ,texas4 ,proc4 ,u4 ,s4 ,nat4 ,mus4 vol4 xvi4 p4 #bfa4 ,foxworthy1 ,f4 ,w4 7#aa7 ,philippine ,gymnosperms4 ,philipp4 ,journ4 ,sci4 7,c7 ,botany1 vol4 vi4 ,no4 #c1 p4 #adi4 ,fraine1 ,e4 de4 7#ab7 ,on the structure and affinities of ,sutcliffia1 in the light of a newly discovered specimen4 ,ann4 ,bot4 vol4 xxvi4 p4 #ajca4 ---- 7#ad7 ,on ,medullosa centrofilis1 a new species of ,medullosa from the ,lower ,coal ,measures4 ,ibid4 vol4 xxviii4 p4 #bea4 ,fritel1 ,p4 ,h4 and ,r4 ,vignier4 7#aa7 tude anatomique de deux bois ocnes4 ,ann4 sci4 nat4 #i1 tome xiv4 p4 #fc4 ,fujii1 ,k4 7#if7 ,on the different views hitherto proposed regarding the morphology of the flowers of ,ginkgo biloba4 ,bot4 ,mag4 ,tokyo1 vol4 x4 ,no4 #aji1 p4 #ac4 ---- 7#aj7 ,some remarks on the ,cretaceous ,fossil ,flora and the causes of extinction4 ,bot4 ,mag4 ,tokyo1 vol4 xxiv4 ,no4 #bhd1 p4 #aig4 ,fujioka1 ,m4 7#ac7 ,studien ber den anatomischen ,bau des ,hlzes der japanischen ,nadelbume4 ,journ4 ,coll4 ,agric4 ,imp4 ,univ4 ,tokyo1 vol4 iv4 ,no4 #d1 p4 #bja4 ,gardner1 ,j4 ,s4 7#hf7 ,a monograph of the ,british ,eocene ,flora1 vol4 ii4 ,gymnospermae4 ,palaeont4 ,soc4 ,london4 ---- 7#hf7 ,second ,report of the ,committee appointed for the purpose of reporting on the ,fossil ,plants of the ,tertiary and ,secondary beds of the ,united ,kingdom4 ,rep4 of the #efth ,meeting ,brit4 ,assoc4 ,geinitz1 ,h4 ,b4 7#db7 ,charakteristik der ,schichten und ,petrefacten des ,schsischen ,kreidegebirges4 ,heft iii4 ,dresden und ,leipzig4 ---- 7#fb7 ,dyas oder die ,zechstein-formation und das ,rothliegende1 ,heft ii4 ,leipzig4 ---- 7#fc7 ber zwei neue ,dyadische ,pflanzen4 ,neues ,jahrb4 ,min4 p4 #ebe4 ---- 7#ga7 ber fossile ,pflanzen aus der ,steinkohlen-,formation am ,altai4 ,leipzig4 ---- 7#gc7 ,versteinerungen aus dem ,brandschiefer der unteren ,dyas von ,weissig bei ,pillnitz in ,schsen4 ,neues ,jahrb4 ,min4 p4 #fha4 ---- 7#ge7 ber neue ,aufschlsse im ,brandschiefer der unteren ,dyas von ,weissig bei ,pillnitz in ,schsen4 ,ibid4 p4 #a4 ---- 7#hj7 ,nachtrge zur ,dyas ,i4 ,mittheil4 aus dem ,k4 ,min4-geol4 und ,praehist4 ,mus4 ,dresden1 ,heft #c4 ,gerry1 ,e4 7#aj7 ,the distribution of the ,bars of ,sanio in the ,coniferales4 ,ann4 ,bot4 vol4 xxiv4 p4 #aai4 ,geyler1 ,t4 and ,f4 ,kinkelin4 7#ij7 ,oberpliocn-,flora aus den ,baugraben des ,klrbeckens bei ,niederrad etc4 ,abh4 ,senck4 ,naturforsch4 ,ges4 ,bd4 xv4 p4 #a4 ,gibbs1 ,l4 ,s4 7#ab7 ,on the ,development of the female strobilus in ,podocarpus4 ,ann4 ,bot4 vol4 xxvi4 p1 #eae4 ,glck1 ,h4 7#jb7 ,eine fossile ,fichte aus dem ,neckerthal4 ,mitt4 ,grossh4 ,bad4 geolog4 ,landesanst4 ,bd4 iv4 ,heft iv4 p4 #cii4 ,goc1 ,m4 ,j4 le4 7#ad7 ,observations on the centripetal and centrifugal xylems in the petioles of ,cycads4 ,ann4 ,bot4 vol4 xxviii4 p4 #ahc4 ,goebel1 ,k4 7#je7 ,organography of ,plants4 ,pt4 ii4 ,oxford4 ,goeppert1 ,h4 ,r4 7#dj7 ber die neulichst im ,basalttuff des hohen ,seelbachkopfes bei ,siegen entdeckten bituminsen und versteinerten ,hlzer1 so wie ber die der ,braunkohlenformation berhaupt4 ,arch4 fr ,min41 ,geog41 etc4 7,karsten und von ,decken71 ,bd4 xiv4 p4 #ahb4 ---- 7#da7 ber den ,bernstein4444 ,uebersicht der ,arbeiten und ,vernderungen der ,schles4 ,ges4 fr ,vaterlnd4 ,kultur4 ,breslau4 ---- 7#da7 ,taxites scalariformis1 eine neue ,art fossilen ,holzes4 ,arch4 fr ,min41 ,geog41 etc4 ,bd4 xv4 p4 #gbg4 ---- 7#dd7 ,ueber die fossilen ,cycadeen berhaupt1 mit ,rcksicht auf die in ,schlesien vorkommenden ,arten4 ,uebersicht ,arbeit4 und ,vernd4 ,schlesisch4 ,ges4 vat4 ,kult4 #ahdc1 p4 #aad4 ,breslau4 ---- 7#de7 ,f4 ,wimmer's ,flora von ,schlesien nebst einer ,uebersicht der ,fossilen ,flora ,schlesiens von ,h4 ,r4 ,goeppert4 ,breslau4 ---- 7#de7 ,description des vgtaux fossiles recueillis par ,m4 ,p4 de ,tchihatcheff en ,sibrie4 ,voyage scientifique dans l',altai oriental1 p4 #cgi4 ,paris4 ---- 7#df7 ,ueber die fossile ,flora der mittleren ,juraschichten in ,oberschlesien4 ,uebers4 ,arbeit4 und ,vernd4 ,schles4 ,ges4 vat4 ,kultur im ,jahre #ahde1 ,breslau1 #ahdf1 p4 #aci4 ---- 7#dg7 ,zur ,flora des ,quadersandsteins in ,schlesien4 ,nachtrag4 ,nov4 ,act4 ,ac4 ,caes4 ,leop4-,car4 vol4 xxii4 p4 #cee4 ---- 7#ej7 ,monographie der fossilen ,coniferen4 ,natuurkundige ,verhand4 ,holland4 ,maatschap4 ,wetenschappen ,haarlem4 ,leiden4 ---- 7#eb7 ,fossile ,flora des bergangsgebirges4 ,nova ,acta ,caes4 ,leop4-,carol4 ,nat4 ,cur4 ,bd4 ,,xx3,i4 7supplement74 ---- 7#ec7 ,ueber die gegenwrtigen ,verhltnisse der ,palontologie in ,schlesien1 so wie ber fossile ,cycadeen4 ,denksch4 ,schles4 ,ges4 fr ,vaterlnd4 ,kultur4 ---- 7#fe7 ,die fossile ,flora der ,permischen ,formation4 ,palaeont4 ,bd4 ii4 p4 #a4 ---- 7#fe7 ber die fossile ,kreideflora und ihre ,leitpflanzen4 ,zeit4 ,deutsch4 geol4 ,ges4 ,bd4 xvii4 p4 #fch4 ---- 7#ff7 ,beitrge zur ,kenntniss fossilen ,cycadeen4 ,neues ,jahrb4 ,min4 p4 #abi4 ---- 7#hj7 ,beitrge zur ,pathologie und ,morphologie fossiler ,stmme4 ,palaeontol4 ,n4,f41 ,bd4 viii4 iii4 p4 #aca4 ---- 7#ha7 ,revision meiner ,arbeiten ber die ,stmme der fossilen ,coniferen1 insbesondere der ,araucariten1 und ber die ,descendenzlehre4 ,bot4 ,cent4 ,bd4 v41 vi4 p4 #cgh4 ,goeppert1 ,h4 ,r4 and ,g4 ,stenzel4 7#ha7 ,die ,medulloseae4 ,palaeontol4 ,n4,f41 ,bd4 viii4 p4 #aac4 ---- 7#hh7 ,nachtrge zur ,kenntniss der ,coniferenhlzer der ,palaeozoischen ,formationen4 ,abh4 ,k4 ,preuss4 ,akad4 ,wiss4 ,berlin4 ,gomes1 ,b4 ,a4 7#fe7 ,vegetaes ,fosseis4 ,flora fossil do ,terrens ,carbonifero das visinhanas dio ,porto1 serra do ,bussaio1 e moinho d'ordem proximo a alcacer do ,sal4 ,comm4 geol4 ,portugal4 ,lisbon4 ,gordon1 ,marjorie4 7#ab7 ,ray-tracheids in ,sequoia sempervirens4 ,new ,phyt4 vol4 xi4 p4 #a4 ,,gordon1 ,w4 ,t4 7#aj7 ,on a new species of ,physostoma from the ,lower ,carboniferous rocks of ,pettycur 7,fife74 ,proc4 ,camb4 ,phil4 ,soc4 vol4 xv4 pt4 v4 p4 #cie4 ---- 7#ab7 ,on ,rhetinangium ,arberi1 a new genus of ,cycadofilices from the ,calciferous sandstone series4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 xlviii4 pt4 iv4 p4 #hac4 ,gothan1 ,w4 7#je7 ,zur ,anatomie lebender und fossiler ,gymnospermer-,hlzer4 ,abh4 ,k4 ,preuss4 geol4 ,landes4 ,n4,f41 ,heft xliv4 p4 #a4 ---- 7#jf7 ,die fossilen ,coniferenhlzer von ,senftenberg4 ,abh4 ,k4 ,preuss4 ,geol4 ,landesanst4 ,bergakad4 ,n4,f41 ,heft xlvi4 p4 #aee4 ---- 7#jf7 ,fossile ,hlzer aus dem ,bathonien von ,russisch-,polen4 ,verhand4 ,k4 ,russ4 ,min4 ,ges4 zu ,st ,petersburg ii1 ,bd4 xliv4 ,lief4 i4 p4 #dce4 ---- 7#jf7 ,piceoxylon ,pseudotsugae als fossiles ,holz4 ,potoni's ,abbild4 und ,beschreib4 ,foss4 ,pflanz4 ,lief4 iv4 #hj4 ---- 7#jg7 ber die ,wandlungen der ,hoftpfelung bei den ,gymnospermen im ,laufe der geologischen ,epochen und ihre physiologische ,bedeutung4 ,sitz4 ,ges4 ,naturforsch4 ,freunde1 ,no4 #b1 p4 #ac4 ---- 7#jg7 ,die ,fossilen ,hlzer von ,knig ,karls ,land4 ,k4 ,svensk4 ,vetenskapsakad4 ,hand4 ,bd4 xlii4 ,no4 #aj1 p4 #a4 ---- 7#jh7 ,die ,fossile ,hlzer von der ,seymour- und ,snow ,hill-,insel4 ,wiss4 ,ergeb4 ,schwedis4 ,sdpolar-,exped4 #aija-jc1 ,bd4 iii4 ,lief4 viii4 ,stockholm4 ---- 7#jh7 ,die ,frage der ,klimadifferenzierung im ,jura und in der ,kreideformation im ,lichte palobotanischer ,tatsachen4 ,jahrb4 ,k4 ,preuss4 ,geol4 ,landes4 fr #aijh1 ,bd4 xxix4 ,th4 ii4 ,heft #b1 p4 #bbj4 ---- 7#ji7 ber ,braunkohlenhlzer des rheinischen ,tertirs4 ,jahrb4 ,k4 ,preuss4 geol4 ,land4 ,bd4 xxx4 ,teil i4 ,heft #c1 p4 #eaf4 ---- 7#aj7 ,die ,fossile ,holzreste von ,spitzbergen4 ,k4 ,svensk4 ,vetenskapsakad4 ,hand4 ,bd4 xlv4 ,no4 viii4 ---- 7#aa7 ber einige ,permo-,carbonische ,pflanzen von der unteren ,tunguska 7,sibirien74 ,zeitsch4 ,deutsch4 ,geol4 ,ges4 ,bd4 lxiii4 ,heft #d1 p4 #dah4 ---- 7#ac7 ,die oberschlesische ,steinkohlenflora4 ,teil i4 ,k4 ,preuss4 geol4 ,landes4 ,n4,f41 ,heft lxxv4 ,gourlie1 ,w4 7#dd7 ,notice of the ,fossil ,plants in the ,glasgow ,museum4 ,proc4 ,phil4 ,soc4 ,glasgow1 vol4 i4 #ahdd1 p4 #aje4 ,grand',eury1 ,c4 7#jj7 ,sur les tiges debout1 les souches et racines de ,cordaites4 ,compt4 ,rend4 tome cxxx4 7,april #cj74 ---- 7#jd7 ,sur les graines des ,neuroptrides4 ,compt4 ,rend4 tome cxxxix4 p4 #bc4 ---- 7#jd7 ,sur les graines des ,neuroptrides4 ,ibid4 p4 #ghb4 ---- 7#je7 ,sur les ,rhabdocarpus1 les graines et l'volution des ,cordaites4 ,ibid4 tome cxl4 p4 #iie4 ---- 7#je7 ,sur les graines de ,sphenopteris1 sur l'attribution des ,codonospermum et sur l'extrme varit des #8graines de fougres4' ,ibid4 p4 #hab4 ---- 7#ac7 ,recherches gobotaniques sur les forts et sols fossiles et sur la vgtation et la flore houillres1 en deux parties et dix livraisons4 ,pt4 i4 ,livr4 ii41 ,paris et ,lige4 ,graner1 7#id7 ,die geographische ,verbreitung der ,holzarten4 ,i4 ,die ,coniferen4 ,forstwissenschaft4 ,centralblatt1 ,berlin4 ,griffith1 ,w4 7#ei7 ,remarks on ,gnetum4 ,trans4 ,linn4 ,soc4 vol4 xxii4 pt4 iv4 p4 #bii4 ,groom1 ,p4 7#aj7 ,remarks on the ,oecology of ,coniferae4 ,ann4 ,bot4 vol4 xxiv4 p4 #bda4 ,groom1 ,p4 and ,w4 ,rushton4 7#ac7 ,the structure of the wood of ,east ,indian species of ,pinus4 ,journ4 ,linn4 ,soc4 vol4 xli4 p4 #deg4 ,groppler1 ,r4 7#id7 ,vergleichende ,anatomie des ,hlzes der ,magnoliaceen4 ,biblioth4 ,bot4 ,bd4 vi4 ,heft #ca4 ,stuttgart4 ,grossenbacher1 ,j4 ,g4 7#ae7 ,medullary spots and their cause4 ,bull4 ,torr4 ,bot4 ,club1 vol4 xlii4 p4 #bbg4 ,guppy1 ,h4 ,b4 7#jf7 ,observations of a ,naturalist in the ,pacific between #ahif and #ahii4 ,london4 ,gutbier1 ,a4 von4 7#di7 ,die ,versteinerungen des ,zechsteingebirges und ,rothliegenden oder des ,permischen ,systems in ,sachsen4 ,dresden and ,leipzig4 ,halle1 ,t4 ,g4 7#aj7 ,a ,gymnosperm with ,cordaitean-like leaves from the ,rhaetic beds of ,scania4 ,arkiv fr ,bot4 ,upsala1 ,bd4 ix4 ,no4 #ad4 ---- 7#ab7 ,on the occurrence of ,dictyozamites in ,south ,america4 ,palaeobot4 ,zeitsch4 ,bd4 i4 ,heft i4 p4 #dj4 ---- 7#ac7 ,some ,mesozoic plant-bearing deposits in ,patagonia and ,tierra del ,fuego and their ,floras4 ,k4 ,svensk4 ,vetenskapsakad4 ,hand4 ,bd4 li4 ,no4 #c4 ---- 7#ac7 ,the ,mesozoic ,flora of ,graham ,land4 ,wiss4 ,ergeb4 ,schwed4 sdpolar4 ,exped4 #aija-jc1 ,bd4 iii4 ,lief4 #ad1 p4 #a4 ---- ,see ,mller1 ,h4 ,j4 and ,t4 ,g4 ,halle 7#ac74 ---- 7#ae7 ,some xerophytic leaf-structures in ,mesozoic plants4 ,geol4 ,fren4 ,stockholm ,frhand4 ,bd4 xxxvii4 ,h4 v4 p4 #dic4 ,hallier1 ,h4 7#je7 ,provisional scheme of the ,natural 7,phylogenetic7 system of ,flowering ,plants4 ,new ,phyt4 vol4 iv4 p4 #aea4 ,harshberger1 ,j4 ,w4 7#ih7 ,water-storage and conduction in ,senecio praecox ,,dc4 from ,mexico4 ,contrib4 ,bot4 ,labt4 7,univ4 ,pennsylvania71 vol4 ii4 ,no4 #a4 ---- 7#aa7 ,phytogeographic ,survey of ,n4 ,america4 7,die ,veget4 der ,erde2 ,engler and ,drude1 xiii4 ,leipzig47 ,harker1 ,a4 7#jf7 ,the ,geological structure of the ,sgurr of ,eigg4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 lxii4 p4 #dj4 ---- 7#jh7 ,the ,geology of the small ,isles of ,inverness-shire4 ,mem4 ,geol4 ,surv4 ,scotland4 ,harpe1 ,p4 de la4 7#fb7 ,see ,bristow1 ,h4 ,w4 ,hartz1 ,n4 7#if7 ,planteforsteninger fra ,cap ,stewart i stgrnland4 ,meddel4 om ,grnland1 xix4 ,copenhagen4 ,hayata1 ,a4 7#jf7 ,on ,taiwania1 a new genus of ,coniferae from the ,island of ,formosa4 ,journ4 ,linn4 ,soc4 vol4 xxxvii4 p4 #ccj4 ---- 7#jg7 ,on ,taiwania and its affinity to other genera4 ,bot4 ,mag4 7,tokyo71 vol4 xxi4 p4 #ba4 ---- 7#aj7 ,botanical ,survey by the ,govt4 of ,formosa4 ,congr4 ,int4 ,bot4 7,bruxelles71 p4 #ei4 ,heer1 ,o4 7#fb7 ,on the ,fossil ,flora of ,bovey ,tracey4 ,phil4 ,trans4 ,r4 ,soc4 vol4 clii4 p4 #ajci4 ---- 7#fh7 i4 ,die in ,nordgrnland1 auf der ,melville-,insel1 im ,banksland1 an ,mackenzie1 im ,island und in ,spitzbergen entdeckten fossilen ,pflanzen4 ,flor4 ,foss4 ,arct4 vol4 i4 ,zrich4 ---- 7#fi7 ,beitrge zur ,kreide-,flora4 ,i4 ,flora von ,moletein in ,mhren4 ,neue ,denksch4 ,allgem4 ,schweiz4 ,ges4 gesammt4 ,naturwiss4 ,bd4 xxiii4 ---- 7#ga7 iii4 ,die ,miocene ,flora und ,fauna ,spitzbergens4 ,flor4 ,foss4 ,arct4 vol4 ii4 ---- 7#ga7 ,beitrge zur ,kreide-,flora4 ,,ii4 ,kreide ,flora von ,quedlinburg4 ,neue ,denksch4 ,allgem4 ,schweiz4 ,ges4 gesammt4 ,naturwiss4 ,bd4 xxiv4 ---- 7#ge7 ii4 ,die ,kreide-,flora der arctischen ,zone4 ,flor4 ,foss4 ,arct4 vol4 iii4 ---- 7#ge7 iii4 ,nachtrge zur ,miocenen ,flora ,grnlands4 ,ibid4 ---- 7#gf7 ,flora ,fossilis ,helvetiae4 ,zrich4 ---- 7#gf7 ber ,permische ,pflanzen von ,fnfkirchen in ,ungarn4 ,mitt4 ,jahrb4 ,k4 ,ung4 ,geol4 ,anst4 ,bd4 v4 ---- 7#gg7 i4 ,beitrge zur fossilen ,flora ,spitzbergens4 ,flor4 ,foss4 ,arct4 vol4 iv4 ---- 7#gg7 ii4 ,beitrge zur ,jura-,flora ,ost ,sibiriens und des ,amurlandes4 ,ibid4 ---- 7#gh7 ii4 ,beitrge zur fossilen ,flora ,sibiriens und des ,amurlandes4 ,ibid4 vol4 iv4 ---- 7#ha7 ,contributions la ,flore du ,portugal4 ,sect4 ,trav4 ,geol4 ,port4 7,lisbon74 ---- 7#ha7 ,zur ,geschichte der ,ginkgo-artigen ,bume4 ,engler's ,bot4 ,jahrb4 ,bd4 i4 p4 #a4 ---- 7#hb7 i4 ,flora fossilis ,grnlandica4 ,flor4 ,foss4 ,arct4 vol4 vi4 ---- 7#hc7 ,flora fossilis ,grnlandica4 ,ibid4 vol4 vii4 ,helmhacher1 ,r4 7#ga7 ,sitzber4 d4 ,k4 ,bhm4 ,ges4 ,wiss4 p4 #ha4 ,henry1 ,a4 7#jf7 ,see ,elwes and ,henry4 ,herzfeld1 ,s4 7#aj7 ,die ,entwicklungsgeschichte der weiblichen ,blte von ,cryptomeria japonica ,don4 ,ein ,beitrag zur ,deutung der ,fruchtschuppe der ,coniferen4 ,sitzber4 ,akad4 ,wiss4 ,wien1 ,bd4 cxix4 ,abt4 i4 p4 #hjg4 ,hick1 ,t4 7#ie7 ,on ,kaloxylon ,hookeri ,will4 and ,lyginodendron ,oldhamium ,will4 ,mem4 ,proc4 ,manchester ,lit4 ,phil4 ,soc4 #d1 vol4 ix4 p4 #aji4 ,hilderbrand1 ,f4 7#fa7 ,die ,verbreitung der ,coniferen4 ,rhein4 und ,westphal4 ,verhand4 ,bd4 xviii4 p4 #aii4 ,hill1 ,t4 ,g4 and ,e4 de ,fraine4 7#aj7 ,on the seedling structure of ,gymnosperms4 ,,iv4 ,ann4 ,bot4 vol4 xxiv4 p4 #cai4 ,hirase1 ,s4 7#ih7 tudes sur la fcundation et l'embryogenie du ,ginkgo biloba4 ,journ4 ,coll4 ,sci4 ,imp4 ,univ4 ,tokyo1 vol4 xii4 p4 #ajc4 ,hhlke1 ,f4 7#jb7 ,ueber die ,harzbehlter und die ,harzbildung bei den ,polypodiaceen und einigen ,phanerogamen4 ,beiheft ,bot4 ,cent4 ,bd4 xi4 p4 #h4 ,holden1 ,h4 ,s4 7#aj7 ,note on a wounded ,myeloxylon4 ,new ,phyt4 vol4 ix4 p4 #bec4 ,holden1 ,ruth4 7#ac7 ,some fossil plants from ,eastern ,canada4 ,ann4 ,bot4 vol4 xxvii4 p4 #bdc4 ---- 7#ac7 ,contributions to the anatomy of ,mesozoic ,conifers4 ,no4 #a4 ,jurassic ,coniferous wood from ,yorkshire4 ,ann4 ,bot4 vol4 xxvii4 p4 #ecc4 ---- 7#ac7 ,cretaceous ,pityoxyla from ,cliffwood1 ,new ,jersey4 ,proc4 ,amer4 ,acad4 ,arts and ,sci4 vol4 xvi4 p4 #fji4 ---- 7#ad7 ,contributions to the anatomy of ,mesozoic ,conifers4 ,,ii4 ,cretaceous ,lignites from ,cliffwood1 ,n4 ,jersey4 ,bot4 ,gaz4 vol4 lviii4 p4 #afh4 ---- 7#ad7 ,on the relation between ,cycadites and ,pseudocycas4 ,new ,phyt4 vol4 xiii4 p4 #ccd4 ---- 7#ae7 ,a ,jurassic wood from ,scotland4 ,ibid4 vol4 xiv4 p4 #bje4 ---- 7#ae7 ,on the cuticles of some ,indian ,conifers4 ,bot4 ,gaz4 vol4 lx4 p4 #bae4 ,hollick1 ,a4 7#ig7 ,the ,cretaceous clay marl exposed at ,cliffwood1 ,n4 ,j4 ,trans4 ,n4 ,y4 ,acad4 ,sci4 vol4 xvi4 p4 #abd4 ---- 7#jd7 ,additions to the ,palaeontology of the ,cretaceous formation on ,long ,island4 ,no4 ,,ii4 ,bull4 ,n4 ,y4 ,bot4 ,gard4 vol4 iii4 ,no4 #aa1 p4 #djc4 ---- 7#jf7 ,the ,cretaceous ,flora of southern ,n4 ,y4 and ,new ,england4 ,u4 ,s4 ,geol4 ,surv4 ,mon4 vol4 l4 ---- 7#jf7 ,systematic ,palaeontology of the ,pleistocene deposits of ,maryland4 ,contributions from the ,new ,york ,bot4 ,gard4 ,no4 #he4 ---- 7#ab7 ,additions to the ,palaeobotany of the ,cretaceous formation on ,long ,island4 ,bull4 ,n4 ,y4 ,bot4 ,gard4 vol4 viii4 ,no4 #bh1 p4 #aed4 ,hollick1 ,a4 and ,e4 ,c4 ,jeffrey4 7#jf7 ,affinities of certain ,cretaceous plant-remains commonly referred to the genera ,dammara and ,brachyphyllum4 ,amer4 ,nat4 vol4 xl4 p4 #ahi4 ,holmes1 ,w4 ,h4 7#gh7 ,fossil ,forests of the ,volcanic ,tertiary formations of the ,yellowstone ,national ,park4 ,ann4 ,rep4 ,geol4 ,geogr4 ,surv4 ,u4,s4,a4 pt4 ii4 p4 #dg4 ,hooker1 ,j4 ,d4 7#eb7 ,dacrydium laxifolium4 ,icones ,plant4 vol4 v4 pl4 #hae4 ---- 7#fj7 ,flora ,tasmanica4 ,london4 ---- 7#fb7 ,on the ,cedars of ,lebanon1 ,taurus1 ,algeria1 and ,india4 ,nat4 ,hist4 ,rev4 p4 #aa4 ---- 7#fc7 ,on ,welwitschia1 a new genus of ,gnetaceae4 ,trans4 ,linn4 ,soc4 vol4 xxiv4 p4 #a4 ,hooker1 ,j4 ,d4 and ,e4 ,w4 ,binney4 7#ee7 ,on the structure of certain limestone nodules enclosed in seams of bituminous coal1 with a description of some ,trigonocarpons contained in them4 ,phil4 ,trans4 ,r4 ,soc4 vol4 cxlix4 ,hrich1 ,o4 7#jf7 ,potoni's ,abbildungen und ,beschreibungen fossiler ,pflanzen-,reste4 ,lief4 iv4 #fi1 #gj4 ,howse1 ,r4 7#hh7 ,a catalogue of ,fossil ,plants from the ,hutton collection4 ,nat4 ,hist4 ,trans4 ,northumberland1 ,durham1 and ,newcastle-upon-,tyne1 vol4 x4 ,hutchinson1 ,a4 ,h4 7#ad7 ,the male gametophyte of ,abies4 ,bot4 ,gaz4 vol4 lvii4 p4 #adh4 ---- 7#ae7 ,on the male gametophyte of ,picea canadensis4 ,ibid4 vol4 lix4 p4 #bhg4 ,jeffrey1 ,e4 ,c4 7#jc7 ,the comparative anatomy and phylogeny of the ,conifers4 ,i4 ,the genus ,sequoia4 ,mem4 ,boston ,soc4 ,nat4 ,hist4 vol4 v4 ,no4 #aj1 p4 #dda4 ---- 7#jd7 ,a fossil ,sequoia from the ,sierra ,nevada4 ,bot4 ,gaz4 vol4 xxxviii4 p4 #cba4 ---- 7#je7 ,the comparative anatomy and phylogeny of the ,conifers4 ,the ,abietineae4 ,mem4 ,boston ,soc4 ,nat4 ,hist4 vol4 vi4 ,no4 #a4 ---- 7#jf7 ,the wound ,reactions of ,brachyphyllum4 ,ann4 ,bot4 vol4 xx4 p4 #chc4 ---- 7#jg7 ,araucariopitys1 a new genus of ,araucarians4 ,bot4 ,gaz4 vol4 xliv4 p4 #dce4 ---- 7#jh7 ,traumatic ray-tracheids in ,cunninghamia sinensis4 ,ann4 ,bot4 vol4 xxii4 p4 #eic4 ---- 7#jh7 ,on the structure of the leaf in ,cretaceous ,pines4 ,ibid4 vol4 xxii4 p4 #bjg4 ---- 7#aj7 ,a new ,prepinus from ,martha's ,vineyard4 ,proc4 ,boston ,soc4 nat4 ,hist4 vol4 xxxiv4 ,no4 #aj1 p4 #ccc4 ---- 7#aj7 ,a new ,araucarian genus from the ,triassic4 ,ibid4 vol4 xxxiv4 ,no4 #i1 p4 #cbe4 ---- 7#aj7 ,on the affinities of ,yezonia4 ,ann4 ,bot4 vol4 xxiv4 p4 #gfi4 ---- 7#aa7 ,the affinities of ,geinitzia gracillima4 ,bot4 ,gaz4 vol4 l4 p4 #ba4 ---- 7#ab7 ,the ,history1 ,comparative ,anatomy and ,evolution of the ,araucarioxylon type4 ,proc4 ,amer4 ,acad4 ,arts ,sci4 vol4 xlviii4 ,no4 #ac1 p4 #ecb4 ---- 7#ad7 ,spore-conditions in hybrids and the mutation hypothesis of de ,vries4 ,bot4 ,gaz4 vol4 lviii4 p4 #cbb4 ,jeffrey1 ,e4 ,c4 and ,m4 ,a4 ,chrysler4 7#jf7 ,on ,cretaceous ,pityoxyla4 ,bot4 ,gaz4 vol4 xlii4 p4 #a4 ---- 7#jf7 ,the ,lignites of ,brandon4 ,contrib4 from the ,phanerogamic ,labt4 of ,harvard ,univ4 ,no4 vi4 ---- 7#jg7 ,the microgametophyte of the ,podocarpineae4 ,amer4 ,nat4 vol4 xli4 ,no4 #dhf1 p4 #cee4 ,jeffrey1 ,e4 ,c4 and ,ruth ,d4 ,cole4 7#af7 ,experimental ,investigations on the genus ,drimys4 ,ann4 ,bot4 vol4 xxx4 p4 #cei4 ,jeffrey1 ,e4 ,c4 and ,r4 ,e4 ,torrey4 7#af7 ,ginkgo and the microsporangial mechanisms of the seed plants4 ,bot4 ,gaz4 vol4 lxii4 p4 #bha4 ,johnson1 ,t4 7#aa7 ,a seed-bearing ,irish ,pteridosperm1 ,crossotheca ,hninghausi ,kidst4 ,sci4 ,proc4 ,r4 ,dublin ,soc4 vol4 xiii4 p4 #a4 ---- 7#ab7 ,heterangium hibernicum sp4 nov4 a seed-bearing ,heterangium from ,co4 ,cork4 ,ibid4 vol4 xiii4 ,no4 #bj4 ---- 7#ad7 ,ginkgophyllum kiltorkense sp4 nov4 ,ibid4 vol4 xiv4 p4 #afi4 ,johnston1 ,r4 ,h4 7#hf7 ,fresh contributions to our knowledge of the ,plants of ,mesozoic age in ,tasmania4 ,papers and ,proc4 ,r4 ,soc4 ,tasmania for #ahhf1 p4 #afj4 ,johnstrup1 ,m4 ,f4 7#hc7 ,recherches sur les fossiles appartenant aux formations ,crtace et ,miocne1 sur la cte occidentale du ,grnland4 ,medd4 om ,grnland1 vol4 v4 ,jones1 ,w4 ,s4 7#ab7 ,the structure of the ,timbers of some common genera of ,coniferous trees4 ,quart4 ,journ4 ,forestry1 ,april4 ---- 7#ac7 ,the minute structure of the wood of ,cupressus macrocarpa4 ,ibid4 ---- 7#ac7 ,ray-tracheids in ,sequoia sempervirens and their pathological character4 ,lampeter4 ,karsten1 ,g4 7#ib7 ,beitrag zur ,entwickelungsgeschichte einiger ,gnetum ,arten4 ,bot4 ,zeit4 p4 #bje4 ---- 7#ic7 ,untersuchungen ber die ,gattung ,gnetum4 ,i4 ,ann4 ,jard4 ,bot4 ,buitenzorg1 tome xi4 p4 #aie4 ---- 7#ic7 ,zur ,entwickelungsgeschichte der ,gattung ,gnetum4 ,cohn's ,beit4 ,biol4 ,pflanz4 vi4 p4 #ccg4 ,kershaw1 ,e4 ,m4 7#ji7 ,the structure and development of the ovule of ,myrica ,gale4 ,ann4 ,bot4 vol4 xxiii4 p4 #cec4 ---- 7#ab7 ,structure and development of the ovule of ,bowenia spectabilis4 ,ibid4 vol4 xxvi4 p4 #fbe4 ,kidston1 ,r4 7#hd7 ,on a new species of ,schtzia from the ,calciferous sandstone of ,scotland4 ,ann4 ,mag4 ,nat4 ,hist4 vol4 xiii4 p4 #gg4 ---- 7#hf7 ,notes on some fossil plants collected by ,mr ,r4 ,dunlop1 ,airdrie1 from the ,lanarkshire coal-field4 ,trans4 ,geol4 ,soc4 ,glasgow1 vol4 viii4 p4 #dg4 ---- 7#ij7 ,the ,yorkshire ,carboniferous ,flora4 ,trans4 ,yorks4 ,nat4 ,union1 pt4 xiv4 ---- 7#ib7 ,notes on some fossil plants from the ,lancashire ,coal ,measures4 ,trans4 ,manchester ,geol4 ,soc4 pt4 xiii4 vol4 xxi4 ---- 7#jd7 ,on the ,fructification of ,neuropteris heterophylla ,brongn4 ,phil4 ,trans4 ,r4 ,soc4 vol4 cxcvii4 p4 #a4 ---- 7#jd7 ,on the ,fructification of ,neuropteris heterophylla ,brongn4 ,proc4 ,r4 ,soc4 vol4 lxxii4 p4 #dhg4 ---- 7#jd7 ,some ,fossil ,plants collected by ,mr ,a4 ,sinclair from the ,ayrshire coalfield4 ,kilmarnock ,glenfield ,ramblers ,soc4 ,annals 7#aija-jd71 ,no4 iv4 ,kilmarnock4 ---- 7#je7 ,preliminary ,note on the occurrence of ,microsporangia in organic connection with the ,foliage of ,lyginodendron4 ,proc4 ,r4 ,soc4 vol4 lxxvi4 p4 #ceh4 ---- 7#aa7 ,les ,vgtaux houillers recueillis dans le ,hainaut ,belge4 ,mm4 ,mus4 ,roy4 d'hist4 nat4 ,belg4 tome iv4 ---- 7#ad7 ,on the ,fossil ,flora of the ,staffordshire coalfields4 ,pt4 iii4 ,the ,fossil ,flora of the ,westphalian series of the ,s4 ,staffs4 coalfield4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 l4 pt4 i4 p4 #gc4 ,kidston1 ,r4 and ,d4 ,t4 ,gwynne-,vaughan4 7#ab7 ,on the ,carboniferous ,flora of ,berwickshire4 ,pt4 i4 ,stenomyelon tuedianum ,kidst4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 xlviii4 pt4 ii4 p4 #bfc4 ,kidston1 ,r4 and ,w4 ,j4 ,jongmans4 7#aa7 ,sur la ,fructification de ,neuropteris obliqua ,brongn4 ,arch4 ,neerl4 sci4 exact4 nat4 iii4 ,b1 tome i4 p4 #be4 ,kirby1 ,j4 ,w4 7#fd7 ,on some remains of ,fishes and ,plants from the #8,upper limestone' of the ,permian series of ,durham4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 xx4 p4 #cdi4 ,kirchner1 ,o41 ,e4 ,t4 ,loew1 and ,c4 ,schrter4 7#jf7 ,die ,coniferen und ,gnetaceen ,mitteleuropas4 ,stuttgart4 ,kirk1 ,t4 7#hi7 ,the ,forest ,flora of ,new ,zealand4 ,wellington4 ,kirsch1 ,s4 7#aa7 ,the ,origin and ,development of resin-canals in the ,coniferae1 with special reference to the ,development of ,thyloses and their correlation with the ,thylosed strands of the ,pteridophytes4 ,trans4 ,r4 ,soc4 ,canada1 sect4 iv4 p4 #dc4 ,kisch1 ,mabel ,h4 7#ac7 ,the ,physiological ,anatomy of the periderm of fossil ,lycopodiales4 ,ann4 ,bot4 vol4 xxvii4 p4 #bha4 ,kleeberg1 ,a4 7#he7 ,die ,markstrahlen der ,coniferen4 7,inaug4 ,diss47 ,bot4 ,zeit4 ,bd4 xliii4 ,klein1 ,l4 7#ha7 ,bau und ,verzweigung einiger dorsiventral gebaute ,polypodiaceen4 ,nov4 ,act4 ,k4 ,leop4 ,car4 ,deutsch4 ,akad4 ,naturforsch4 ,bd4 xlii4 ,no4 #g1 p4 #cce4 ,knowlton1 ,f4 ,h4 7#hi7 ,description of the fossil woods and lignites from ,arkansas4 ,ann4 ,rep4 ,geol4 ,surv4 ,arkansas1 vol4 ii4 p4 #bdi4 ---- 7#hi7 ,fossil wood and ,lignite of the ,potomac formation4 ,bull4 ,u4 ,s4 ,geol4 ,surv4 ,no4 #ef4 ---- 7#ij7 ,a ,revision of the genus ,araucarioxylon of ,kraus1 with the compiled descriptions and partial synonymy of the species4 ,proc4 ,u4 ,s4 ,mus4 vol4 xii4 p4 #fja4 ---- 7#ic7 ,the ,laramie and the overlying ,livingstone formation in ,montana4 ,report on the ,flora4 ,bull4 ,u4 ,s4 ,geol4 ,surv4 ,no4 #aje4 ---- 7#ii7 ,fossil ,flora of the ,yellowstone ,national ,park4 ,monographs4 xxxii4 ,u4 ,s4 ,geol4 ,surv4 pt4 ii4 chap4 xiv4 ---- 7#jj7 ,flora of the ,montana formation4 ,bull4 ,u4 ,s4 ,geol4 ,surv4 ,no4 #afc4 ---- 7#je7 ,the geology of the ,perry basin in ,south-eastern ,maine1 with a chapter on the fossil plants4 ,u4 ,s4 ,geol4 ,surv4 ,prof4 ,papers1 ,no4 #ce4 ---- 7#aa7 ,the correct technical name for the ,dragon tree of the ,kentish ,rag4 ,geol4 ,mag4 v1 vol4 viii4 p4 #dfg4 ---- 7#ad7 ,the ,jurassic ,flora of ,cape ,lisburne1 ,alaska4 ,u4 ,s4 ,geol4 ,surv4 ,prof4 ,papers1 ,no4 #he-;,d1 p4 #ci4 ,kny1 ,l4 7#aj7 ber die ,verteilung des ,holzparenchyma bei ,abies pectinata ,,dc4 ,ann4 ,jard4 ,bot4 ,buit4 #b1 ,suppl4 iii4 p4 #fde4 ,koetlitz1 ,r4 7#ih7 ,observations on the geology of ,franz ,josef ,land4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 liv4 p4 #fbj4 ,kosmovsky1 ,c4 7#ib7 ,quelques mots sur les couches vgtaux fossiles dans la ,russie orientale et en ,sibrie4 ,bull4 ,soc4 ,imp4 ,nat4 ,moscou ,n4,s41 tome v4 p4 #agj4 ,kramer1 ,a4 7#he7 ,beitrge zur ,kenntniss der ,entwickelungsgeschichte und des anatomischen ,baues der ,fruchtbltter der ,cupressineen und der ,placenten der ,abietineen4 ,flora1 xliii4 p4 #eai4 ,krasser1 ,f4 7#ia7 ber die fossile ,flora der rhtischen ,schichten ,persiens4 ,sitzber4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 c4 ,abth4 i4 p4 #dac4 ---- 7#ig7 ,constantine ,freiherr von ,ettingshausen4 ,oesterr4 bot4 ,zeitsch4 ,nos4 #i and #aj4 ---- 7#jc7 ,konstantin von ,ettingshausen's ,studien ber die fossile ,flora von ,ouricanga in ,brasilien4 ,sitzber4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 cxii4 ,abt4 i4 p4 #heb4 ---- 7#je7 ,fossile ,pflanzen aus ,transbaikalien der ,mongolei und ,mandschurei4 ,denksch4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 lxxviii4 p4 #ehi4 ---- 7#ji7 ,zur ,kenntniss der fossilen ,flora der ,lunzer ,schichten4 ,jahrb4 ,k4k4 geol4 ,reichs4 ,wien1 ,bd4 lix1 ,heft i4 p4 #aja4 ---- 7#ab7 ,williamsonia in ,sardinien4 ,sitzber4 ,k4 ,akad4 ,wien1 ,bd4 cxxi4 ,abt4 i4 p4 #idd4 ---- 7#ac7 ,die fossile ,flora der ,williamsonien bergenden ,juraschichten von ,sardinien4 ,ibid4 ,bd4 cxxii4 ,kraus1 ,g4 7#fd7 ,mikroskopische ,untersuchungen ber der ,bau lebenden ,nadelhlzer4 ,wrzb4 ,naturwiss4 ,zeitsch4 ,bd4 v4 p4 #add4 ---- 7#ff7 ber den ,bau der ,cycadeenfiedern4 ,prings4 ,jahrb4 ,bd4 iv4 p4 #cje4 ---- 7#hc7 ,beitrge zur ,kenntniss fossiler ,hlzer4 ,i4 ,hlzer aus den ,schwefelgruben ,siciliens4 ,abh4 ,naturf4 ,ges4 ,halle1 ,bd4 xvi4 p4 #gi4 ---- 7#ib7 ,beitrge zur ,kenntniss fossiler ,hlzer4 ,abh4 ,naturforsch4 ,ges4 ,halle1 ,bd4 xvii4 p4 #fg4 ---- 7#if7 ,physiologisches aus den ,tropen4 ,ann4 ,jard4 ,bot4 ,buit4 vol4 xiii4 p4 #bag4 ,krusel1 ,r4 7#ac7 ,beitrge zur ,kenntniss der ,hlzer aus der ,schlesischen ,braunkohle4 ,teil i4 7,inaug4 ,diss4 ,breslau47 ,bot4 ,cent4 ,bd4 cxxiii4 p4 #abc4 ,kryshtofovich1 ,a4 7#aj7 ,jurassic ,plants from ,ussuriland4 ,mem4 ,com4 ,geol4 ,n4,s41 ,livr4 #ef4 ---- 7#ae7 ,plant remains from ,jurassic lake-deposits of ,transbaikalia4 ,mm4 ,soc4 ,imp4 ,russe ,mineralog4 #b1 li4 ,kubart1 ,b4 7#jh7 ,pflanzenversteinerungen enthaltende ,knollen aus dem ,ostrau-,karwiner ,kohlenbecken4 ,sitzber4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 cxvii4 ,abt4 i4 p4 #egc4 ---- 7#aa7 ,corda's sphaerosiderite aus dem ,steinkohlenbecken ,radnitz-,braz in ,bhmen nebst ,bemerkungen ber ,chorionopteris gleichenioides ,corda4 ,ibid4 ,bd4 cxx4 ,abt4 i4 p4 #ajce4 ---- 7#aa7 ,podocarpoxylon ,schwendae1 ein fossiles ,holz von ,altersee 7,obersterreich74 sterr4 bot4 ,zeitsch4 ,no4 #e1 p4 #afa4 ---- 7#ad7 ber die ,cycadofilicineen ,heterangium und ,lyginodendron aus dem ,ostrauer ,kohlenbecken4 sterr4 bot4 ,zeitsch4 ,no4 i4 ii4 p4 #h4 ,kurtz1 ,f4 7#jc7 ,remarks upon ,mr ,e4 ,a4 ,arber's communication on the ,clarke collection of ,fossil ,plants from ,new ,south ,wales4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 lix4 p4 #be4 ,kutorga1 ,s4 7#db7 ,beitrag zur ,palaeontologie ,russlands4 ,verhand4 ,russ4-,kais4 ,mineral4 ,ges4 ,st ,petersburg4 ---- 7#dd7 ,zweiter ,beitrag zur ,palaeontologie ,russlands4 ,ibid4 p4 #fb4 ,land1 ,w4 ,j4 ,g4 7#jd7 ,spermatogenesis and ,oogenesis in ,ephedra trifurca4 ,bot4 ,gaz4 vol4 xxxviii4 p4 #a4 ,lang1 ,w4 ,h4 7#ig7 ,studies in the ,development and ,morphology of ,cycadean sporangia4 ,i4 ,the microsporangia of ,stangeria paradoxa4 ,ann4 ,bot4 vol4 xi4 p4 #dba4 ---- 7#jj7 ,studies in the ,development and ,morphology of ,cycadean sporangia4 ,,ii4 ,the ovule of ,stangeria paradoxa4 ,ibid4 vol4 xiv4 p4 #bha4 ,lange1 ,t4 7#ij7 ,beitrge zur ,kenntniss der ,flora des ,aachener ,sandes4 ,zeitsch4 ,deutsch4 geol4 ,ges4 ,bd4 xlii4 p4 #feh4 ,laurent1 ,l4 7#ab7 ,flore fossile des ,schistes de ,manat 7,puy-de-,dme74 ,ann4 ,mus4 d'hist4 nat4 ,marseille 7,geol471 tome xiv4 p4 #c4 ,lawson1 ,a4 ,a4 7#jd7 ,the gametophytes1 fertilization1 and embryo of ,cryptomeria japonica4 ,ann4 ,bot4 vol4 xviii4 p4 #dag4 ---- 7#ji7 ,the gametophytes and embryo of ,pseudotsuga ,douglasii4 ,ibid4 vol4 xxiii4 p4 #afc4 ---- 7#aj7 ,the gametophytes and embryo of ,sciadopitys verticillata4 ,ibid4 vol4 xxiv4 p4 #djc4 ,lebour1 ,g4 ,a4 7#gg7 ,illustrations of ,fossil ,plants2 being an autotype reproduction of selected drawings4 ,london4 ,lesquereux1 ,l4 7#gd7 ,contributions to the ,fossil ,flora of the ,western ,territories4 ,pt4 i4 ,the ,cretaceous ,flora4 ,rep4 ,u4 ,s4 ,geol4 ,surv4 ,territ4 vol4 vi4 ---- 7#gh7 ,on the ,cordaites and their related generic divisions1 in the ,carboniferous formation of the ,united ,states4 ,proc4 ,amer4 ,phil4 ,soc4 7,philadelphia71 vol4 xvii4 p4 #cae4 ---- 7#hc7 ,contributions to the ,fossil ,flora of the ,western ,territories4 ,pt4 iii4 ,the ,cretaceous and ,tertiary ,floras4 ,u4 ,s4 ,geol4 ,surv4 ,territ4 vol4 iii4 ---- 7#ia7 ,the ,flora of the ,dakota group4 ,monographs ,u4 ,s4 ,geol4 ,surv4 vol4 xvii4 ,leuthardt1 ,f4 7#jc7 ,die ,keuper ,flora von ,neuewelt bei ,basel4 ,abh4 ,schweiz4 palaeont4 ,ges4 ,bd4 xxx4 p4 #a4 ,lignier1 ,o4 7#ib7 ,la nervation taenioptride de folioles de ,cycas et le tissu de transfusion4 ,bull4 soc4 ,linn4 ,normandie #d1 vol4 vi4 fasc4 #a4 ---- 7#id7 ,la nervation des ,cycades est dichotomique4 ,assoc4 ,fran4 pour l'avancement de sci4 7,caen74 ---- 7#id7 ,vgtaux ,fossiles de ,normandie4 ,structure et affinits du ,bennettites ,morierei ,s4 and ,m4 sp4 ,mm4 soc4 ,linn4 ,normand4 tome xviii4 p4 #a4 ---- 7#ie7 ,vgtaux fossiles de ,normandie4 ,,ii4 ,contributions la flore liassique de ,ste ,honorine-la-,guillaume 7,orne74 ,ibid4 vol4 xviii4 ---- 7#ja7 ,ibid4 ,,iii4 tude anatomique du ,cycadeoidea micromyela ,mor4 ,ibid4 vol4 xx4 p4 #cca4 ---- 7#jc7 ,le fruit du ,williamsonia gigas ,carr4 ,mm4 soc4 ,linn4 ,normand4 vol4 xxi4 p4 #ai4 ---- 7#jc7 ,la ,fleur des ,gntaces est-celle intermdiaire entre celle des ,gymnospermes et celle des ,angiospermes8 ,bull4 soc4 ,linn4 ,normand4 #e1 vol4 vii4 p4 #ee4 ---- 7#jd7 ,notes complmentaires sur la structure du ,bennettites ,morierei ,s4 and ,m4 ,bull4 soc4 ,linn4 ,normand4 #e1 vol4 viii4 p4 #c4 ---- 7#jf7 ,radiculites reticulatus1 radicelle fossile de ,squoine4 ,bull4 soc4 bot4 ,france1 tome vi4 iii41 p4 #aic4 ---- 7#jg7 ,sur un moule litigieux de ,williamsonia gigas 7,l4 and ,h47 ,carr4 ,ibid4 #f1 vol4 #a4 ---- 7#jg7 ,vgtaux fossiles de ,normandie4 ,,iv4 ,bois divers 7sr4 #a74 ,mm4 soc4 ,linn4 ,normand4 vol4 xxii4 p4 #bci4 ---- 7#ji7 ,le ,bennettites ,morierei 7,s4 and ,m47 ,lignier ne serait-il pas d'origine infracrtace8 ,bull4 soc4 ,linn4 ,normand4 #f1 vol4 ii4 p4 #bad4 ---- 7#aa7 ,le ,bennettites ,morierei 7,s4 and ,m47 ,lign4 se reproduisait probablement par parthnognse4 ,bull4 soc4 bot4 ,france #d1 tome xi4 p4 #bbd4 ---- 7#aa7 ,les 8,radiculites reticulatus0 ,lign4 soit probablement des radicelles de ,cordaitales4 ,assoc4 ,fran4 ,avanc4 ,sci4 xl4 7,dijon71 p4 #eji4 ,see also ,lignier 7#jf74 ---- 7#ab7 ,stomates des cailles intersminales chez le ,bennettites ,morierei 7,s4 and ,m474 ,ibid4 tome xii4 p4 #dbe4 ---- 7#ac7 ,vgtaux fossiles de ,normandie4 ,,vii4 ,contributions la ,flore ,jurassique4 ,mm4 soc4 ,linn4 ,normand4 vol4 xxiv4 p4 #fi4 ---- 7#ac7 ,diffrenciation des tissus dans le ,bourgeon vgtatif du ,cordaites lingulatus ,b4 ,ren4 ,ann4 sci4 nat4 #g1 vol4 xvii4 p4 #bcc4 ,lignier1 ,o4 et ,a4 ,tison4 7#aa7 ,les ,gntales sont des ,angiospermes aptales4 ,compt4 ,rend4 ,jan4 #bc4 ---- 7#ab7 ,les ,gntales1 leurs fleurs et leur position systmatique4 ,ann4 sci4 nat4 ,n4,s44 ---- 7#ac7 ,l'ovule tritgument des ,gnetum est probablement un axe d'inflorescence4 ,bull4 soc4 bot4 ,france #d1 tome xiii4 p4 #fd4 ---- 7#ac7 ,un nouveau ,sporange ,sminiforme1 ,mittagia seminiformis1 gen4 et sp4 nov4 ,mm4 ,soc4 ,linn4 ,normandie1 tome xxiv4 p4 #di4 ,lima1 ,w4 de4 7#hh7 ,flora ,fossil de ,portugal4 ,monographia do ,genero ,dicranophyllum4 ,comm4 dos ,trab4 geol4 ,portugal4 ,lindley1 ,j4 ,see ,murchison and ,lyell 7#bi74 ,lingelsheim1 ,a4 7#jh7 ber die ,braunkohlenhlzer von ,saarau4 ,jahres-,ber4 ,schles4 ,ges4 ,vaterlnd4 ,cultur4 ,bd4 lxxxv4 ,lloyd1 ,f4 ,e4 7#jb7 ,vivipary in ,podocarpus4 ,torreya1 ii4 p4 #aac4 ,lomax1 ,j4 7#jb7 ,on some features in relation to ,lyginodendron oldhamium4 ,ann4 ,bot4 vol4 xvi4 p4 #fja4 ,lotsy1 ,j4 7#ii7 ,contributions to the life-history of the genus ,gnetum4 ,ann4 ,jard4 ,bot4 ,buit4 #b1 vol4 i4 p4 #df4 ---- 7#ji7 ,vortrge ber botanische ,stammesgeschichte4 ,bd4 ii4 ,jena4 ---- 7#aa7 ,ibid4 ,bd4 iii4 ,ludwig1 ,r4 7#fa7 ,fossile ,pflanzen aus der ltesten ,abtheilung der ,rheinisch-,wetterauer ,tertir-,formation4 ,palaeontograph4 ,bd4 viii4 p4 #ci4 ---- 7#fi7 ,fossile ,pflanzenreste aus den palolithischen ,formation der ,umgegend von ,dillenburg1 ,biedenkopf und ,friedberg und aus den ,saalfeldischen4 ,ibid4 ,bd4 xvii4 p4 #aje4 ,lyon1 ,h4 ,l4 7#jd7 ,the ,embryogeny of ,ginkgo4 ,minnesota ,bot4 ,stud4 xxiii4 p4 #bge4 ,mc,bride1 ,t4 ,h4 7#ic7 ,a new ,cycad4 ,amer4 ,geologist1 vol4 xii4 p4 #bdh4 ,mackie1 ,s4 ,j4 7#fb7 ,the ,dragon ,tree of the ,kentish ,rag4 ,geologist1 vol4 v4 p4 #dja4 ,mc,lean1 ,r4 ,c4 7#ab7 ,two ,fossil prothalli from the ,lower ,coal ,measures4 ,new ,phyt4 vol4 xi4 p4 #cje4 ,mc,nab1 ,w4 ,r4 7#gj7 ,on the structure of a ,lignite from the ,old ,red ,sandstone4 ,trans4 ,bot4 ,soc4 ,edinburgh1 vol4 x4 p4 #cab4 ,mahlert1 ,a4 7#he7 ,beitrge zur ,kenntniss der ,anatomie der ,laubbltter der ,coniferen mit besonderer ,bercksichtigung des ,spaltffnungs-,apparates4 ,bot4 ,cent4 ,bd4 xxiv4 p4 #ed4 ,malloizel1 ,g4 and ,r4 ,zeiller4 7,n4,d47 ,bibliographie et tables iconographiques 7,o4 ,heer74 ,stockholm4 ,mansell-,pleydell1 ,j4 ,c4 7#he7 ,notes on a cone from the ,inferior ,oolite ,beds of ,sherborne4 ,proc4 ,dorset ,nat4 ,hist4 ,antiq4 ,field ,club1 vol4 v4 p4 #ada4 ,mantell1 ,g4 7#bg7 ,illustrations of the ,geology of ,sussex4 ,london4 ---- 7#dc7 ,description of some fossil plants from the chalk formation of the south-east of ,england4 ,proc4 ,geol4 ,soc4 vol4 iv4 p4 #cd4 ---- 7#df7 ,description of some ,fossil ,fruits from the ,chalk formation of the south-east of ,england4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ii4 p4 #ea4 ,marion1 ,a4 ,f4 7#hd7 ,sur les caractres d'une ,conifre tertiaire1 voisine des ,dammares 7,doliostrobus ,sternbergi74 ,compt4 ,rend4 vol4 xciv4 p4 #hba4 ,marsh1 ,a4 ,s4 7#ad7 ,notes on the ,anatomy of ,stangeria paradoxa4 ,new ,phyt4 vol4 xiii4 p4 #ah4 ,marty1 ,p4 7#jh7 ,sur la ,flore fossile de ,lugarde 7,cantal74 ,compt4 ,rend4 vol4 cxlvii4 p4 #cie4 ,maslen1 ,a4 ,j4 7#aj7 ,see ,scott and ,maslen4 ---- 7#aa7 ,the structure of ,mesoxylon ,sutcliffi 7,scott74 ,ann4 ,bot4 vol4 xxv4 p4 #cha4 ,massalongo1 ,a4 7#ei7 ,studii sulla ,flora ,fossile e geologia stratigrafica del ,senigalliese4 ,verona4 ,massalongo1 ,a4 and ,g4 ,scarabelli4 7#eh7 ,studii sulla ,flora ,fossile e geologia stratigrafica del ,senigalliese4 ,verona4 ,masters1 ,m4 ,t4 7#ia7 ,review of some points in the comparative morphology1 anatomy1 and life-history of the ,coniferae4 ,journ4 ,linn4 ,soc4 vol4 xxviii4 p4 #bcf4 ---- 7#ic7 ,notes on the genera of ,taxaceae and ,coniferae4 ,ibid4 vol4 xxx4 p4 #a4 ---- 7#jj7 ,taxodium and ,glyptostrobus4 ,journ4 ,bot4 7,february1 #aijj74 ,matte1 ,h4 7#jd7 ,recherches sur l'appareil libro-ligneux des ,cycades4 ,caen4 ---- 7#jh7 ,sur le dveloppement morphologique et anatomique des ,cycadaces4 ,mm4 soc4 ,linn4 ,normand4 tome xxiii4 ,matthew1 ,g4 ,f4 7#aj7 ,revision of the ,flora of the ,little ,river group4 ,trans4 ,r4 ,soc4 ,canada1 sect4 iv4 vol4 iii4 #c1 p4 #gg4 ,mercklin1 ,c4 ,e4 von4 7#ee7 ,palaeodendrologicon ,rossicum4 ,st ,petersburg4 ,miller1 ,h4 7#eh7 ,the ,cruise of the ,betsey4 ,edinburgh4 ,miquel1 ,f4 ,a4 ,w4 7#db7 ,monographia ,cycadearum4 ---- 7#dg7 ,collectanea nova ad ,cycadearum cognitionem4 ,linnaea1 ,bd4 xix4 p4 #daa4 ---- 7#ea7 ,over de ,rangschikking der fossiele ,cycadeae4 ,tijdsch4 ,wiss4 ,nat4 ,wet4 vol4 iv4 p4 #bje4 ---- 7#fi7 ,on the sexual organs of the ,cycadaceae4 ,journ4 ,bot4 vol4 vii4 p4 #fd4 ,mirande1 ,m4 7#je7 ,recherches sur le dveloppement et l'anatomie de ,cassythaces4 ,ann4 ,sci4 nat4 ix1 vol4 i4 p4 #aha4 ,miyake1 ,k4 7#jf7 ber die ,spermatozoiden von ,cycas revoluta4 ,ber4 ,deutsch4 bot4 ,ges4 ,bd4 xxiv4 p4 #gh4 ---- 7#aj7 ,the ,development of the gametophytes and embryogeny in ,cunninghamia sinensis4 ,beiheft ,bot4 ,cent4 ,bd4 xxxvii4 ,abt4 i4 ,heft #a4 ,mogan1 ,l4 7#jc7 ,untersuchungen ber eine fossile ,konifere4 ,sitzber4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 cxii4 ,abt4 i4 p4 #hbi4 ,mohl1 ,h4 von4 7#fb7 ,einige anatomische und physiologische ,bemerkungen ber das ,holz der ,baumwurzeln4 ,bot4 ,zeit4 p4 #bbe4 ,mller1 ,h4 7#jc7 ,bidrag till ,bornholms ,fossila ,flora 7,rht och ,lias74 ,gymnospermer4 ,k4 ,svensk4 ,vetenskapsakad4 ,hand4 ,bd4 xxxvi4 ,no4 vi4 ,mller1 ,h4 ,j4 and ,t4 ,g4 ,halle4 7#ac7 ,the ,fossil ,flora of the ,coal-bearing deposits of south-eastern ,scania4 ,arkiv ,bot4 7,stockholm71 ,bd4 xiii4 ,no4 #g4 ,morire1 ,j4 7#fi7 ,note sur deux vgtaux trouvs dans le dpartement du ,calvados4 ,mm4 soc4 ,linn4 ,normand4 vol4 xv4 ,morris1 ,j4 7#dj7 ,memoir to illustrate a ,geological map of ,cutch 7,grant1 ,c4 ,w474 ,trans4 ,geol4 ,soc4 #b1 vol4 v4 pt4 ii4 p4 #bhi4 ---- 7#da7 ,remarks upon the ,recent and ,fossil ,cycadeae4 ,ann4 ,mag4 ,nat4 ,hist4 vol4 vii4 p4 #aaj4 ---- 7#ed7 ,a ,catalogue of ,british ,fossils4 ,london4 ,mller1 ,c4 7#ij7 ,ueber die ,balken in den ,holzelementen der ,coniferen4 ,ber4 ,deutsch4 bot4 ,ges4 ,bd4 viii4 p4 #ag4 ,murchison1 ,sir ,r4 and ,r4 ,harkness4 7#fd7 ,on the ,permian rocks of the ,north-west of ,england1 and their extension into ,scotland4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 xx4 p4 #add4 ,murchison1 ,sir ,r4 and ,c4 ,lyell4 7#bi7 ,on the ,tertiary ,freshwater formations of ,aix1 in ,provence1 including the coal-field of ,fuveau4 ,description of plants by ,j4 ,lindley4 ,edinburgh ,new ,phil4 ,journ4 p4 #bhg4 ,nakamura1 ,y4 7#hc7 ,ueber den anatomischen ,bau des ,hlzes der wichtigsten ,japanischen ,coniferen4 ,unters4 aus dem ,forstbot4 ,instit4 zu ,mnchen4 iii4 ,berlin4 ,nathorst1 ,a4 ,g4 7#ge7 ,om en ,cycadkotte frn den rtiska formationens lager vid ,tinkarp i ,skne4 fver4 ,k4 ,vetenskapsakad4 ,frh4 ,no4 #aj4 ---- 7#gh7 ,om ,ginkgo crenata ,brauns sp4 frn sandstenen vid ,senstedt nra ,braunschweg4 ,ibid4 ,no4 #c4 ---- 7#hj7 ,ngra anmrkningar om ,williamsonia1 ,carruthers4 ,ibid4 ,no4 #i4 ---- 7#ha7 ,berttelse1 afgifven till ,kongl4 ,vetenskaps-,akad4 fver4 ,k4 ,vetenskapsakad4 ,frhand4 ,no4 #a4 ---- 7#hf7 ,om ,floran i ,sknes kolfrande ,bildningar4 ,i4 ,floran vid ,bjuf4 ,sver4 geol4 ,unters4 ser4 ,c1 ,nos4 #bg1 #cc1 #he 7#ahgh-hf74 ---- 7#hh7 ,nya anmrkningar om ,williamsonia4 fver4 ,k4 ,vetenskapsakad4 ,frh4 ,no4 #f4 ---- 7#hi7 ,sur la prsence du ,genre ,dictyozamites1 ,old4 dans les ,couches ,jurassiques de ,bornholm4 vers4 ,k4 ,dansk4 ,vidensk4 ,selsk4 ,frhandl4 p4 #if4 ---- 7#ic7 ,beitrge zur ,geologie und ,palaeontologie der ,republik ,mexico 7,felix und ,link71 ,th4 ii4 ,heft i4 ,leipzig4 ---- 7#ig7 ,zur ,mesozoischen ,flora ,spitzbergens4 ,k4 ,svensk4 ,vetenskapsakad4 ,hand4 ,bd4 xxx4 ,no4 #a1 p4 #e4 ---- 7#ig7 ,nachtrgliche ,bemerkungen ber die ,mesozoische ,flora ,spitzbergens4 fvers4 ,k4 ,vet4-,akad4 ,frhand4 ,no4 #h4 ---- 7#ii7 ,the ,norwegian ,north ,polar ,expedition #ahic-if4 ,scientific ,results1 edit4 ,f4 ,nansen4 ,,iii4 ,fossil ,plants from ,franz ,josef ,land4 ,london and ,christiania4 ---- 7#jb7 ,beitrge zur ,kenntniss einiger ,mesozoischen ,cycadophyten4 ,k4 ,svensk4 ,vetenskapsakad4 ,hand4 ,bd4 xxxvi4 ,no4 #d4 ---- 7#jf7 ,om ngra ,ginkgovaxter frn ,kolgrufvorna vid ,stabbarp i ,skane4 ,lunds ,univ4 rsskrift ,n4,f41 ,afd4 ii4 ,bd4 ii4 ,no4 #h4 ---- 7#jg7 ber ,trias- und ,jurapflanzen von der ,insel ,kotelny4 ,mm4 ,acad4 ,imp4 ,sci4 ,st ,petersburg1 vol4 xxi4 ,no4 #b4 ---- 7#jg7 ,palobotanische ,mitteilungen4 #b4 ,die ,kutikula der ,bltter von ,dictyozamites ,johnstrupi ,nath4 ,k4 ,svensk4 ,vetenskapsakad4 ,hand4 ,bd4 xlii4 ,no4 #e4 ---- 7#jg7 ,ibid4 ,i4 ,pseudocycas1 eine neue ,cycadophytengattung aus den ,cenomanen ,kreideablagerungen ,grnlands4 ---- 7#jh7 ber die ,untersuchungen kutinisierter fossiler ,pflanzenteile4 ,palobot4 ,mitt4 #d-f4 ,k4 ,svensk4 ,vetenskapsakad4 ,hand4 ,bd4 xliii4 ,no4 #f1 p4 #c4 ---- 7#jh7 ,palobot4 ,mitt4 #g4 ber ,palissya1 ,stachyotaxus and ,palaeotaxus4 ,ibid4 ,bd4 xliii4 ,no4 #h4 ---- 7#ji7 ,palobot4 ,mitt4 #h4 ber ,williamsonia1 ,wielandia1 ,cycadocephalus und ,weltrichia4 ,ibid4 ,bd4 xlv4 ,no4 #d4 ---- 7#ji7 ber die ,gattung ,nilssonia ,brongn4 mit besonderer ,bercksichtigung ,schwedischen ,arten4 ,k4 ,svensk4 ,vetenskapsakad4 ,hand4 ,bd4 xliii4 ,no4 #ab4 ---- 7#aj7 ,excursion ,c #c4 ,dpts fossilifres 7plantes7 quaternaires de ,skne4 ,compt4 ,rend4 du ,x,ie ,congrs ,gol4 ,internat4 p4 #acec4 ---- 7#aa7 ,palobot4 ,mitt4 #i4 ,neue ,beitrge zur ,kenntniss der ,williamsonia-,blten4 ,k4 ,svensk4 ,vetenskapsakad4 ,hand4 ,bd4 xlvi4 ,no4 #d4 ---- 7#aa7 ,bemerkungen ber ,weltrichia ,fr4 ,braun4 ,arkiv ,bot4 7,k4 ,svensk4 ,vetenskapsakad4 ,stockholm71 ,bd4 ii4 ,no4 #g1 p4 #a4 ---- 7#aa7 ,fossil floras of the ,arctic ,regions as evidence of geological climates4 ,geol4 ,mag4 v1 vol4 viii4 p4 #bag4 ---- 7#aa7 ,palobot4 ,mitt4 #aj4 ber die ,gattung ,cycadocarpidium ,nath4 nebst einigen ,bemerkungen ber ,podozamites4 ,k4 ,svensk4 ,vetenskapsakad4 ,hand4 ,bd4 xlvi4 ,no4 #h4 ---- 7#ab7 ,die ,mikrosporophylle von ,wielandiella4 ,arkiv ,bot4 ,stockholm1 ,bd4 xii4 ,no4 #f1 p4 #a4 ---- 7#ab7 ,palobot4 ,mitt4 #aa4 ,zur ,kenntniss der ,cycadocephalus ,blte4 ,k4 ,svensk4 ,vetenskapsakad4 ,hand4 ,bd4 xlviii4 ,no4 #b4 ---- 7#ab7 ,einige palobotanische ,untersuchungsmethoden4 ,palobot4 ,zeitsch4 ,bd4 i4 ,heft i4 p4 #bf4 ---- 7#ac7 ,how are the names ,williamsonia and ,wielandiella to be used8 ,a question of nomenclature4 ,geol4 ,fren4 ,stockholm ,frh4 ,bd4 xxxv4 ,h4 vi4 p4 #cfa4 ---- 7#ac7 ,die pflanzenfhrenden ,horizonte innerhalb der ,grenzschichten des ,jura und der ,kreide ,spitzbergens4 ,geol4 ,fren4 ,stockholm ,frh4 ,bd4 xxxv4 ,h4 iv4 p4 #bgc4 ---- 7#ad7 ,zur ,fossilen ,flora der ,polarlnder4 ,teil i4 ,lief4 iv4 ,nachtrge zur ,plaozoischen ,flora ,spitzbergens4 ,stockholm4 ---- 7#ae7 ,zur ,devonflora des westlichen ,norwegens4 ,bergens ,mus4 ,aarbog1 ,no4 #g4 ---- 7#ae7 ,tertire ,pflanzenreste aus ,ellesmere-,land4 ,rep4 second ,norwegian ,arct4 ,exped4 in the 8,fram0 #ahih-jb1 ,no4 #ce4 ,kristiania4 ,negri1 ,g4 7#ad7 ,sopra alcuni legni fossili del ,gebel ,tripolitano4 ,boll4 ,soc4 geol4 ,ital4 vol4 xxxiii4 p4 #cba4 ,nestler1 ,a4 7#ie7 ,ein ,beitrag zur ,anatomie der ,cycadeenfiedern4 ,pringsheim's ,jahrb4 ,bd4 xxvii4 p4 #cda4 ,newberry1 ,j4 ,s4 7#ed7 ,new ,fossil ,plants from ,ohio4 ,annals of ,science2 including the ,transactions of the ,american ,association for the ,advancement of ,science1 vol4 i4 ,cleveland1 #ahec-ed1 p4 #aaf4 ---- 7#gc7 ,report of the ,geological ,survey of ,ohio1 vol4 i4 ---- 7#hh7 ,rhaetic ,plants from ,honduras4 ,amer4 ,journ4 ,sci4 vol4 xxxvi4 p4 #cdb4 ,newberry1 ,j4 ,s4 and ,a4 ,hollick4 7#ie7 ,the ,flora of the ,amboy clays4 ,u4 ,s4 ,geol4 ,surv4 ,monographs1 vol4 xxvi4 ,newton1 ,e4 ,t4 and ,j4 ,j4 ,h4 ,teall4 7#ig7 ,notes on a collection of rocks and fossils from ,franz ,josef ,land1 made by the ,jackson-,harmsworth ,exped4 during #ahid-if4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 liii4 p4 #dgg4 ---- 7#ih7 ,additional notes on rocks and fossils from ,franz ,josef ,land4 ,ibid4 vol4 liv4 p4 #fdf4 ,noack1 ,f4 7#hg7 ,der ,einfluss des ,klimas auf die ,cuticularisation und ,verholzung der ,nadeln einiger ,coniferen4 ,pringsheim's ,jahrb4 ,bd4 xviii4 p4 #eai4 ,noelle1 ,w4 7#aj7 ,studien zur vergleichenden ,anatomie und ,morphologie der ,koniferen ,wurzeln mit ,rcksicht auf die ,systematik4 ,bot4 ,zeit4 p4 #afi4 ,norn1 ,c4 ,o4 7#jh7 ,zur ,kenntniss der ,entwickelung von ,saxegothaea conspicua ,lind4 ,svensk4 ,bot4 ,tids4 ,bd4 ii4 ,h4 ii4 p4 #aja4 ,oliver1 ,f4 ,w4 7#jb7 ,on some points of apparent resemblance in certain ,fossil and ,recent ,gymnosperm seeds4 ,new ,phyt4 vol4 i4 p4 #ade4 ---- 7#jc7 ,the ovules of the older ,gymnosperms4 ,ann4 ,bot4 vol4 xvii4 p4 #dea4 ---- 7#jd7 ,notes on ,trigonocarpus1 ,brongn4 and ,polylophospermum1 ,brongn41 two genera of ,palaeozoic seeds4 ,new ,phyt4 vol4 iii4 p4 #if4 ---- 7#je7 ber die neuentdeckten ,samen der ,steinkohlenfarne4 ,biolog4 ,centralblatt1 ,bd4 xxv4 ,no4 #ab1 p4 #dja4 ---- 7#jf7 ,the seed1 a chapter in ,evolution4 ,rep4 #gfth ,meeting ,brit4 ,assoc4 7,york71 p4 #gbe4 ---- 7#jg7 ,note on the ,palaeozoic seeds ,trigonocarpus and ,polylophospermum4 ,ann4 ,bot4 vol4 xxi4 p4 #cjc4 ---- 7#ji7 ,on ,physostoma elegans ,will4 an archaic type of seed from the ,palaeozoic rocks4 ,ibid4 vol4 xxiii4 p4 #gc4 ---- 7#ac7 ,makers of ,modern ,botany4 ,a collection of ,biographies by living ,botanists1 edited by ,f4 ,w4 ,oliver4 ,cambridge4 ,oliver1 ,f4 ,w4 and ,e4 ,j4 ,salisbury4 7#aa7 ,on the structure and affinities of the ,conostoma group of ,palaeozoic seeds4 ,ann4 ,bot4 vol4 xxv4 p4 #a4 ,oliver1 ,f4 ,w4 and ,d4 ,h4 ,scott4 7#jc7 ,on ,lagenostoma ,lomaxi1 the seed of ,lyginodendron4 ,proc4 ,r4 ,soc4 vol4 lxxi4 p4 #dgg4 ---- 7#jd7 ,on the structure of the ,palaeozoic seed ,lagenostoma ,lomaxi1 with a statement of the evidence upon which it is referred to ,lyginodendron4 ,phil4 ,trans4 ,r4 ,soc4 vol4 cxcvii4 p4 #aic4 ,osborne1 ,t4 ,g4 ,b4 7#ji7 ,the lateral roots of ,amyelon radicans ,will4 and their ,mycorhiza4 ,ann4 ,bot4 vol4 xxiii4 p4 #fjc4 ,palibin1 ,j4 7#ja7 ,quelques donnes relatives aux dbris vgtaux contenus dans les sables blancs et les grs quartzeux de la ,russie mridionale4 ,bull4 ,com4 ,geol4 tome xx4 p4 #ddg4 ---- 7#jd7 ,pflanzenreste vom ,sichota-,alin ,gebirge4 ,verhand4 ,k4 ,russ4 ,mineral4 ,ges4 ,bd4 xlii4 ,lief4 i4 p4 #ca4 ,patrick1 ,j4 ,s4 7#dd7 ,on the ,fossil vegetables of the ,sandstone of ,ayrshire4 ,ann4 ,mag4 ,nat4 ,hist4 vol4 xiii4 p4 #bhc4 ,pavolini1 ,a4 ,f4 7#ji7 ,la ,stangeria paradoxa ,th4 ,moore4 ,nuov4 ,giorn4 ,bot4 ,italiano ,n4,s41 vol4 xvi4 p4 #cce4 ,firenze4 ,pax1 ,f4 7#jg7 ,beitrge zur fossilen ,flora der ,karpathen4 ,engler's ,bot4 ,jahrb4 ,bd4 xxxviii4 p4 #bgb4 ,pearson1 ,h4 ,h4 ,w4 7#jf7 ,notes on ,south ,african ,cycads4 ,i4 ,trans4 ,s4 ,afr4 ,phil4 ,soc4 vol4 xvi4 p4 #cda4 ---- 7#jf7 ,some observations on ,welwitschia mirabilis4 ,phil4 ,trans4 ,r4 ,soc4 vol4 cxcviii4 p4 #bfe4 ---- 7#ji7 ,further observations on ,welwitschia4 ,ibid4 vol4 cc4 p4 #cca4 ---- 7#ab7 ,on the ,microsporangium and ,microspore of ,gnetum1 with some notes on the structure of the ,inflorescence4 ,ann4 ,bot4 vol4 xxvi4 p4 #fjc4 ---- 7#ae7 ,a note on the inflorescence and flower of ,gnetum4 ,ann4 ,bolus ,herb4 vol4 i4 pt4 iv4 p4 #aeb4 ---- 7#ae7 ,notes on the ,morphology of certain ,structures concerned in ,reproduction in the genus ,gnetum4 ,trans4 ,linn4 ,soc4 vol4 viii4 pt4 viii4 p4 #caa4 ,penhallow1 ,d4 ,p4 7#ia7 ,see ,dawson and ,penhallow4 ---- 7#ig7 ,myelopteris topekensis n4 sp4 a new ,carboniferous ,plant4 ,bot4 ,gaz4 vol4 xxiii4 p4 #ae4 ---- 7#jj7 ,notes on the ,north ,american species of ,dadoxylon4 ,trans4 ,r4 ,soc4 ,canada #b1 vol4 vi4 sect4 iv4 p4 #ea4 ---- 7#jb7 ,notes on ,cretaceous and ,tertiary ,plants of ,canada4 ,trans4 ,r4 ,soc4 ,canada #b1 vol4 viii4 sect4 iv4 p4 #ca4 ---- 7#jc7 ,notes on ,tertiary ,plants4 ,ibid4 vol4 ix4 sect4 iv4 p4 #hc4 ---- 7#jd7 ,the anatomy of the ,north ,american ,coniferales together with certain exotic species from ,japan and ,australia4 ,amer4 ,nat4 vol4 xxxviii4 pp4 #bdc1 #ebc4 ---- 7#jg7 ,a ,manual of the ,north ,american ,gymnosperms4 ,boston4 ---- 7#jh7 ,report on a collection of ,fossil woods from the ,cretaceous of ,alberta4 ,the ,ottawa ,naturalist1 vol4 xxii4 ,no4 iv4 p4 #hb4 ,phillips1 ,j4 7#ga7 ,the ,geology of ,oxford and the valley of the ,thames4 ,oxford4 ,pilger1 ,r4 7#jc7 ,taxaceae4 ,das ,pflanzenreich 7,a4 ,engler71 ,heft xviii4 7iv4 #e74 ,leipzig4 ,platen1 ,p4 7#jh7 ,untersuchungen fossiler ,hlzer aus dem ,westen der ,vereinigten ,staaten von ,nordamerika4 ,leipzig4 ,pomel1 ,a4 7#di7 ,matriaux pour servir la flore fossile des terrains jurassiques de la ,france4 ,amt4 ,ber4 ,versam4 ,ges4 deutsch4 ,naturforsch4 und rzte4 ,aachen4 ,porsch1 ,c4 7#je7 ,der ,spaltffnungsapparat im ,lichte der ,phylogenie4 ,jena4 ---- 7#aj7 ,ephedra campylopoda ,c4 ,a4 ,mey4 eine entomophile ,gymnosperme4 ,ber4 ,deutsch4 ,bot4 ,ges4 ,bd4 xxviii4 p4 #djd4 ,potoni1 ,h4 7#hh7 ,die fossile ,pflanzen-,gattung ,tylodendron4 ,jahrb4 ,k4 ,preuss4 geol4 ,landes4 p4 #caa4 ---- 7#if7 ,ueber ,autochthonie von ,carbonkohlen-,fltze und der ,senftenberger ,braunkohlen-,fltze4 ,ibid4 7#ahie71 p4 #a4 ---- 7#jb7 ,fossile ,hlzer aus der oberen ,kreide ,deutsch-stafrikas4 ,die ,reisen des ,bergassessors ,dr ,dantz in ,deutsch-stafrika in den ,jahren #ahih-jj4 ,mitt4 aus den deutschen ,schutzgebieten1 ,bd4 xv4 ,heft iv4 p4 #bbg4 ---- 7#jc7 ,pflanzenreste aus der ,jura-formation4 ,durch ,asien4 ,bd4 iii4 ,lief4 i4 ,berlin4 ---- 7#jd7 ,abbildungen und ,beschreibungen fossilen ,pflanzen-,reste4 ,lief4 ii4 ,no4 #dj4 ,k4 ,preuss4 geol4 ,landes4 ,bergakad4 ,potoni1 ,h4 and ,c4 ,bernard4 7#jd7 ,flore ,dvonienne de l'tage ,h4 de ,barrande4 ,leipzig4 ,prankerd1 ,t4 ,l4 7#ab7 ,on the structure of the ,palaeozoic seed ,lagenostoma ovoides ,will4 ,journ4 ,linn4 ,soc4 vol4 xl4 p4 #dfa4 ,prestwich1 ,j4 7#ed7 ,on the structure of the strata between the ,london ,clay and the ,chalk in the ,london and ,hampshire ,tertiary systems4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 x4 p4 #ge4 ,raciborski1 ,m4 7#ia7 ,flora ,retycka ,plnocnego ,stoku ,gr witokrzyskich4 ,rozprawy ,wydzialu ,akad4 ,umiej4 ,krakowie1 tom4 xxiii4 ---- 7#ib7 ,przyczynek do ,flory ,retyckiej ,polski4 ,ibid4 tom4 xxii4 p4 #a4 ---- 7#ib7 ,cycadeoidea ,niedwiedzkii nov4 sp4 ,akad4 wiss4 ,krak4 ,oktober #ahib4 ,radais1 ,m4 7#id7 ,l'anatomie compare du fruit des ,conifres4 ,ann4 ,sci4 nat4 #g1 vol4 xix4 p4 #afe4 ,ratte1 ,f4 7#hg7 ,note on two new fossil plants from the ,wianametta shales4 ,proc4 ,linn4 ,soc4 ,n4,s4,w4 #b1 vol4 i4 p4 #ajgh4 ---- 7#hh7 ,additional evidence on ,fossil ,salisburiae from ,australia4 ,proc4 ,linn4 ,soc4 ,n4,s4,w4 #b1 vol4 ii4 p4 #aei4 ,rattray1 ,c4 7#ac7 ,notes on the pollination of some ,south ,african ,cycads4 ,trans4 ,r4 ,soc4 ,s4 ,africa1 vol4 iii4 p4 #bei4 ,reid1 ,clement and ,eleanor ,m4 ,reid4 7#jh7 ,on the ,preglacial ,flora of ,britain4 ,journ4 ,linn4 ,soc4 vol4 xxxviii4 p4 #bjf4 ---- 7#aj7 ,the ,lignites of ,bovey ,tracey4 ,phil4 ,trans4 ,r4 ,soc4 vol4 cci4 p4 #afa4 ---- 7#ae7 ,the ,pliocene ,floras of the ,dutch-,prussian border4 ,meded4 ,rijksopsporing ,delfstoffen1 ,no4 #f4 ,the ,hague4 ,renault1 ,b4 7#gi7 ,sur un nouveau groupe de tiges fossiles silicifies de l'poque houillire4 ,compt4 ,rend4 tome lxxxviii4 p4 #ce4 ---- 7#hj7 ,sur une nouvelle espce de ,poroxylon4 ,compt4 ,rend4 tome xci4 p4 #hfj4 ---- 7#hj7 ,cours de ,botanique fossile4 ,tome i4 ,paris4 ---- 7#hc7 ,cours de ,botanique fossile4 ,tome iii4 ---- 7#he7 ,cours de ,botanique fossile4 ,tome iv4 ---- 7#hg7 ,note sur le ,clathropodium ,morieri4 ,bull4 soc4 ,linn4 ,normand4 #d1 vol4 i4 p4 #c4 ---- 7#hh7 ,les ,plantes fossiles4 ,paris4 ---- 7#hi7 ,sur un nouveau genre fossile de tige cycadenne4 ,compt4 ,rend4 vol4 cix4 p4 #aagc4 ---- 7#if7 ,note sur le genre ,mtacordaite4 ,soc4 d'hist4 nat4 d',autun4 ,renault1 ,b4 and ,r4 ,zeiller4 7#he7 ,sur un nouveau type de ,cordaite4 ,compt4 ,rend4 vol4 c4 p4 #hfg4 ---- 7#hf7 ,sur quelques ,cycades houillires4 ,ibid4 vol4 cii4 p4 #cbe4 ,rendle1 ,a4 ,b4 7#if7 ,gymnospermae4 ,the ,plants of ,milanji1 ,nyasa-,land1 collected by ,mr ,a4 ,whyte4 ,trans4 ,linn4 ,soc4 vol4 iv4 #b1 p4 #fj4 ---- 7#jd7 ,the ,classification of ,flowering plants4 ,vol4 i4 ,cambridge4 ,renier1 ,a4 7#jg7 ,trois espces nouvelles1 ,sphenopteris ,dumonti1 ,s4 ,corneti et ,dicranophyllum ,richiri du ,houiller sans ,houille de ,baudour1 ,hainaut4 ,ann4 soc4 gol4 ,belg4 vol4 xxxiv4 ,mm4 p4 #aha4 ---- 7#aj7 ,documents pour l'tude de la palontologie du terrain houiller4 ,lige4 ---- 7#aj7 ,palontologie du ,terrain ,houiller4 ,lige4 ,renner1 ,o4 7#jd7 ber ,zwitterblthen bei ,juniperus communis4 ,flora1 ,bd4 xcii4 p4 #ib4 ,richards1 ,j4 ,t4 7#hd7 ,on ,scottish ,fossil ,cycadaceous leaves contained in the ,hugh ,miller ,collection4 ,proc4 ,r4 ,phys4 ,soc4 ,edinburgh4 ,robertson1 ,agnes4 7#jb7 ,notes on the anatomy of ,macrozamia heteromera ,moore4 ,proc4 ,camb4 ,phil4 ,soc4 vol4 xii4 pt4 i4 p4 #a4 ---- 7#jd7 ,studies in the ,morphology of ,torreya californica ,torrey4 ,new ,phyt4 vol4 iii4 p4 #bje4 ---- 7#jf7 ,some points in the ,morphology of ,phyllocladus alpinus ,hook4 ,ann4 ,bot4 vol4 xx4 p4 #bei4 ---- 7#jg7 ,the ,taxoideae2 a phylogenetic study4 ,new ,phyt4 vol4 vi4 p4 #ib4 ,rosen1 ,f4 7#aa7 ,die biologische ,stellung der abessinischen ,baumlobelie 7,lobelia ,rhynchopetalum74 ,beit4 ,biol4 ,pflanzen4 ,cohn und ,rosen1 ,bd4 x4 ,heft ii4 p4 #bfe4 ,rothert1 ,w4 7#ii7 ,ueber parenchymatische ,tracheiden und ,harzgnge im ,mark von ,cephalotaxus-,arten4 ,ber4 deutsch4 bot4 ,ges4 ,bd4 xvii4 p4 #bge4 ,rushton1 ,w4 7#ae7 ,structure of the wood of ,himalayan ,junipers4 ,journ4 ,linn4 ,soc4 vol4 xliii4 p4 #a4 ---- 7#af7 ,the ,development of #8,sanio's ,bars' in ,pinus ,inops4 ,ann4 ,bot4 vol4 xxx4 p4 #dai4 ,russow1 ,e4 7#gb7 ,vergleichende ,untersuchungen der ,leitbndel-,kryptogamen4 ,mm4 l',acad4 ,imp4 ,sci4 ,st ,ptersbourg vii1 tome xix4 p4 #a4 ---- 7#hc7 ,zur ,kenntniss des ,holzes1 insonderheit des ,coniferenholzes4 ,bot4 ,cent4 ,bd4 xiii4 p4 #bi4 ,salisbury1 ,e4 ,j4 7#ac7 ,methods of ,palaeobotanical reconstruction4 ,ann4 ,bot4 vol4 xxvii4 p4 #bgc4 ---- 7#ad7 ,on the structure and relationship of ,trigonocarpus shorensis4 ,ann4 ,bot4 vol4 xxviii4 p4 #ci4 ,sanday1 ,elizabeth4 7#jg7 ,see ,berridge and ,sanday4 ,sandberger1 ,f4 von4 7#fd7 ,die ,flora der oberen ,steinkohlenformation im badischer ,schwarzwalde4 ,verh4 ,nat4 ,ver4 ,carlsruhe1 vol4 i4 p4 #cj4 ---- 7#ij7 ,ueber ,steinkohlenformation und ,rothliegendes im ,schwarzwald und deren ,flora4 ,jahrb4 ,k4k4 geol4 ,reichs4 ,bd4 xl4 ,heft i4 p4 #gg4 ,sanio1 ,k4 7#gd7 ,anatomie der ,gemeinen ,kiefer 7,pinus silvestris ,l474 ,pringsheim's ,jahrb4 ,bd4 ix4 p4 #gh4 ,saporta1 ,g4 de4 7#fb7 tudes sur la vgtation du sud-est de la ,france l'poque ,tertiaire4 ,ann4 ,sci4 ,nat4 tome xvi4 #d1 p4 #cji4 ---- 7#fb7 ,ibid4 tome xvii4 p4 #aia4 ---- 7#fe7 ,ibid4 tome iii4 #e1 p4 #e4 ---- 7#fe7 ,ibid4 tome iv4 p4 #e4 ---- 7#fh7 ,ibid4 tome ix4 p4 #e4 ---- 7#fh7 ,note sur la flore fossile des regions arctiques4 ,bull4 soc4 gol4 ,france #b1 tome xxv4 p4 #cae4 ---- 7#gc7 tudes sur la vgtation du sud-est de la ,france l'poque ,tertiaire4 ,ann4 ,sci4 nat4 tome xvii4 #e1 p4 #ha4 ---- 7#gd7 ,sur la prsence d'une ,cycade dans le dpt ,miocne de ,koumi 7,eube74 ,compt4 ,rend4 vol4 lxxviii4 p4 #acah4 ---- 7#ge7 ,sur la dcouverte de deux types nouveaux de ,conifres dans les schistes ,permiens de ,lodve 7,hrault74 ,ibid4 vol4 lxxx4 p4 #ajag4 ---- 7#gh7 ,observations sur la nature des vgtaux runis dans le groupe des ,noeggerathia2 gnralits et type du ,noeggerathia foliosa ,sternb4 ,ibid4 vol4 lxxxvi4 p4 #gdf4 ---- 7#gh7 ,ibid4 ,types du ,noeggerathia flabellata ,l4 and ,h4 et du ,n4 cyclopteroides ,goepp4 ,ibid4 vol4 lxxxvi4 p4 #hja4 ---- 7#gh7 ,ibid4 ,type des ,noeggerathia expansa et cuneifolia de ,brongniart4 ,ibid4 vol4 lxxxvi4 p4 #hfj4 ---- 7#gh7 ,sur le nouveau groupe ,palozoique des ,dolerophylles4 ,ibid4 vol4 lxxxvii4 p4 #cic4 ---- 7#hb7 ,sur quelques types de vgtaux rcemment observs l'tat fossile4 ,ibid4 vol4 xliv4 p4 #ibb4 ---- 7#hd7 ,palontologie ,franaise4 ,plantes ,jurassiques1 tome iii4 ---- 7#ia7 ,ibid4 tome iv4 ,types ,proangiospermiques4 ---- 7#ic7 ,revue des travaux de ,palontologie vgtale4 ,rev4 ,gn4 tome v4 p4 #a4 ,saporta1 ,g4 de and ,a4 ,f4 ,marion4 7#gf7 ,recherches sur les vgtaux fossiles de ,meximieux4 ,arch4 ,mus4 d'hist4 nat4 de ,lyon4 ,lyon4 ---- 7#gh7 ,rvision de la flore ,heersienne de ,gelinden4 ,mm4 cour4 et ,mm4 sav4 trang4 tome xli4 7,acad4 roy4 sci4 etc4 ,belg474 ---- 7#he7 ,l'volution du ,rgne vgtal4 ,tome i4 ,les ,phanrogames4 ,paris4 ,saxton1 ,w4 ,t4 7#aj7 ,contributions to the life-history of ,widdringtonia cupressoides4 ,bot4 ,gaz4 vol4 l4 p4 #ca4 ---- 7#aj7 ,contributions to the life-history of ,callitris4 ,ann4 ,bot4 vol4 xxiv4 p4 #eeg4 ---- 7#aj7 ,notes on the anatomy of ,widdringtonia and ,callitris4 ,s4 ,african ,journ4 ,sci4 p4 #bhb4 ---- 7#aj7 ,the development of the embryo of ,encephalartos4 ,bot4 ,gaz4 vol4 xlix4 p4 #ac4 ---- 7#ab7 ,note on an abnormal prothallus of ,pinus maritima ,l4 ,ann4 ,bot4 vol4 xxvi4 p4 #idc4 ---- 7#ac7 ,contributions to the life-history of ,actinostrobus pyramidalis ,miq4 ,ann4 ,bot4 vol4 xxvii4 p4 #cba4 ---- 7#ac7 ,the classification of ,conifers4 ,new ,phyt4 vol4 xii4 p4 #bdb4 ---- 7#ac7 ,contributions to the life-history of ,tetraclinis articulata1 ,masters1 with some notes on the ,phylogeny of the ,cupressoideae and the ,callitroideae4 ,ann4 ,bot4 vol4 xxvii4 p4 #egg4 ,schauroth1 ,c4 von4 7#eb7 ,herr von ,schauroth an ,herrn ,beyrich4 ,zeit4 ,deutsch4 geol4 ,ges4 ,bd4 iv4 p4 #ech4 ,schenk1 ,a4 7#fg7 ,ueber die ,flora der schwarzen ,schiefer von ,raibl4 ,wrzburg4 ,naturwiss4 ,zeitsch4 vol4 vi4 p4 #aj4 ---- 7#fh7 ,ueber die ,pflanzenreste des ,muschelkalkes von ,recoaro4 ,benecke's ,geog4-,pal4 ,beit4 ,bd4 ii4 ,mnchen4 ---- 7#fh7 ,beitrge zur ,flora der ,vorwelt4 ,palaeontol4 ,bd4 xvi4 p4 #bah4 ---- 7#ga7 ,die fossilen ,pflanzen der ,wernsdorfer ,schichten in der ,nordkarpathen4 ,ibid4 ,bd4 xix4 p4 #a4 ---- 7#hj7 ,ueber fossile ,hlzer aus der ,libyschen ,wste4 ,bot4 ,zeit4 ,bd4 xxxviii4 p4 #feg4 ---- 7#hb7 ,ueber ,medullosa elegans4 ,engler's ,jahrb4 ,bd4 iii4 p4 #aef4 ---- 7#hb7 ,die von dem ,gebrdern ,schagintweit in ,indien gesammelten fossilen ,hlzer4 ,engler's ,bot4 ,jahrb4 ,bd4 iii4 p4 #cec4 ---- 7#hc7 ,fossile ,hlzer der libyschen ,wste 7,die ,libysche ,wste1 ,bd4 iii474 ---- 7#hi7 ,ueber ,medullosa ,cotta4 ,abh4 ,k4 ,schs4 ,ges4 ,wiss4 ,bd4 xv4 p4 #ebc4 ,schlechtendal1 ,d4 von4 7#jb7 ,thuja occidentalis thuringiaca4 ,zeitsch4 ,naturwiss4 ,stuttgart4 ,bd4 lxxv4 p4 #cc4 ,schmalhausen1 ,j4 7#hc7 ,die ,pflanzenreste der ,steinkohlenformation am stlichen ,abhange des ,ural ,gebirges4 ,mm4 ,acad4 ,s4 ,ptersbourg1 vol4 xxxi4 ,no4 #ac4 ---- 7#hc7 ,beitrge zur ,tertir ,flora sd-west ,russlands4 ,palaeontol4 ,abh4 7,dames and ,kayser71 ,bd4 i4 ,heft iv4 p4 #bhe4 ---- 7#hg7 ,die ,pflanzenreste der ,artinskischen und ,permischen ,ablagerungen im ,osten des ,europischen ,russlands4 ,mm4 ,com4 gol4 ,st ,ptersbourg1 vol4 ii4 ,no4 iv4 p4 #a4 ---- 7#ij7 ,wissenschaftliche ,resultate der von der ,akad4 der ,wiss4 zur ,erforschung des ,janalandes und der ,neusibirischen ,inseln in den ,jahren #ahhe1 #ahhf ausgesandten ,expedition4 ,abt4 ii4 ,tertire ,pflanzen der ,insel ,neusibirien4 ,mm4 l'acad4 ,imp4 ,sci4 ,st ,ptersbourg vii1 vol4 xxxvii4 ,no4 #e4 ,schneider1 ,w4 7#ac7 ,vergleichend-morphologische ,untersuchungen ber die ,kurztriebe einiger ,arten von ,pinus4 ,flora ,n4,f41 ,bd4 v4 p4 #che4 ,schroeter1 ,c4 7#hj7 ,untersuchung ber fossile ,hlzer aus der arctischen ,zone4 7,heer's ,flor4 ,foss4 ,arct4 vol4 vi4 #ahhb47 ---- 7#ig7 ,ueber die ,vielgestaltigkeit der ,fichte 7,picea excelsa ,link474 ,vierteljahr4 ,naturforsch4 ,ges4 ,zrich4 ,jahrg4 xlii4 p4 #abe4 ,schuster1 ,j4 7#aa7 ,ueber ,goeppert's ,raumeria im ,zwinger zu ,dresden4 ,sitzber4 ,k4 ,bayer4 ,akad4 ,wiss4 p4 #dhi4 ---- 7#aa7 ,weltrichia und die ,bennettitales4 ,k4 ,svensk4 ,vetenskapsakad4 ,hand4 ,bd4 xlvi4 ,no4 #aa4 ---- 7#aa7 ,pagiophyllum ,weismanni im unteren ,hauptmuschelkalk von ,wrzburg4 ,geog4 ,jahresheft1 ,bd4 xiii4 p4 #adi4 ---- 7#aa7 ,bemerkungen ber ,podozamites4 ,ber4 ,deutsch4 ,bot4 ,ges4 ,bd4 xix4 ,heft #g1 p4 #dej4 ,schtze1 ,e4 7#ja7 ,beitrge zur ,kenntniss der ,triassischen ,koniferen-,gattungen ,pagiophyllum1 ,voltzia1 ,widdringtonites4 ,jahresheft ,ver4 ,vat4 ,naturkunde1 ,stuttgart1 p4 #bef4 ,scott1 ,d4 ,h4 7#ig7 ,the anatomical characters presented by the peduncle of ,cycadaceae4 ,ann4 ,bot4 vol4 xi4 p4 #cii4 ---- 7#ii7 ,on the structure and affinities of ,fossil ,plants from the ,palaeozoic rocks4 ,,iii4 ,on ,medullosa anglica1 a new representative of the ,cycadofilices4 ,phil4 ,trans4 ,r4 ,soc4 vol4 cxci4 p4 #ha4 ---- 7#ii7 ,on the primary wood of certain ,araucarioxylons4 ,ann4 ,bot4 vol4 xiii4 p4 #fae4 ---- 7#jb7 ,on the ,primary structure of certain ,palaeozoic stems with the ,dadoxylon type of wood4 ,trans4 ,r4 ,soc4 vol4 xl4 p4 #cca4 ---- 7#jc7 ,the origin of seed-bearing plants4 ,r4 ,instit4 ,great ,brit4 ,weekly ,evening meeting1 ,febry4 #ae4 ---- 7#jf7 ,on ,sutcliffia insignis1 a new type of ,medulloseae from the ,lower ,coal ,measures4 ,trans4 ,linn4 ,soc4 vol4 vii4 pl4 iv4 p4 #de4 ---- 7#ji7 ,the ,palaeontological ,record4 ,,ii4 ,plants4 ,darwin and ,modern ,science1 ,art4 xii4 ,cambridge4 ---- 7#ab7 ,the structure of ,mesoxylon ,lomaxi and ,m4 poroxyloides4 ,ann4 ,bot4 vol4 xxvi4 p4 #ajaa4 ---- 7#aa7 ,the ,evolution of ,plants4 ,london4 ---- 7#ad7 ,on ,medullosa pusilla4 ,proc4 ,r4 ,soc4 vol4 lxxxvii4 p4 #bba4 ---- 7#ae7 ,the ,heterangiums of the ,british ,coal ,measures4 ,british ,assoc4 7,manchester ,meeting #aiae74 7,abstract47 ,scott1 ,d4 ,h4 and ,e4 ,c4 ,jeffrey4 7#ad7 ,on ,fossil ,plants showing structure1 from the base of the ,waverley shale of ,kentucky4 ,phil4 ,trans4 ,r4 ,soc4 vol4 #bje1 p4 #cae4 ,scott1 ,d4 ,h4 and ,a4 ,j4 ,maslen4 7#jg7 ,the structure of the ,palaeozoic seeds ,trigonocarpus ,parkinsoni ,brongn4 and ,t4 ,oliveri sp4 nov4 ,ann4 ,bot4 vol4 xxi4 p4 #hi4 ---- 7#aj7 ,on ,mesoxylon1 a new genus of ,cordaitales4 ,ibid4 vol4 xxiv4 p4 #bcf4 ,sellards1 ,e4 ,h4 7#jc7 ,codonotheca1 a new type of spore-bearing organ from the ,coal ,measures4 ,amer4 ,journ4 ,sci4 vol4 xvi4 p4 #hg4 ---- 7#jg7 ,notes on the spore-bearing organ ,codonotheca and its relationship with the ,cycadofilices4 ,new ,phyt4 vol4 vi4 p4 #age4 ,sernander1 ,r4 7#ic7 ,die ,einwanderung der ,fichte in ,skandinavien4 ,engler's ,bot4 ,jahrb4 ,bd4 xv4 p4 #a4 ,seward1 ,a4 ,c4 7#ij7 ,tylodendron ,weiss and ,voltzia heterophylla ,brong4 ,geol4 ,mag4 vol4 vii4 #c1 p4 #bah4 ---- 7#ic7 ,on the genus ,myeloxylon4 ,ann4 ,bot4 vol4 xxv4 p4 #a4 ---- 7#id7 ,on ,rachiopteris ,williamsoni sp4 nov41 a new ,fern from the ,coal-,measures4 ,ibid4 vol4 viii4 p4 #bjg4 ---- 7#if7 ,a new species of ,conifer1 ,pinites ,ruffordi1 from the ,english ,wealden formation4 ,journ4 ,linn4 ,soc4 vol4 xxxii4 p4 #dag4 ---- 7#if7 ,notes on the geological history of ,monocotyledons4 ,ann4 ,bot4 vol4 x4 p4 #bje4 ---- 7#ig7 ,on ,encephalartos ,ghellinckii ,lem41 a rare ,cycad4 ,proc4 ,camb4 ,phil4 ,soc4 vol4 ix4 p4 #cdj4 ---- 7#ig7 ,a contribution to our knowledge of ,lyginodendron4 ,ann4 ,bot4 vol4 xi4 p4 #fe4 ---- 7#ig7 ,on the association of ,sigillaria and ,glossopteris in ,s4 ,africa4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 liii4 p4 #cae4 ---- 7#ig7 ,on the leaves of ,bennettites4 ,proc4 ,camb4 ,phil4 ,soc4 vol4 ix4 p4 #bgc4 ---- 7#jj7 ,notes on some ,jurassic plants in the ,manchester ,museum4 ,mem4 ,proc4 ,manchester ,lit4 ,phil4 ,soc4 vol4 xliv4 pt4 iii4 ,no4 #h4 ---- 7#jc7 ,on the occurrence of ,dictyozamites in ,england1 with ,remarks on ,european and ,eastern ,mesozoic ,floras4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 lix4 p4 #bag4 ---- 7#jf7 ,notes on ,cycads4 ,proc4 ,camb4 ,phil4 ,soc4 vol4 xiii4 pt4 v4 p4 #bii4 ---- 7#jg7 ,permo-,carboniferous plants from ,kashmir4 ,rec4 ,geol4 ,surv4 ,india1 vol4 xxxvi4 pt4 i4 p4 #eg4 ---- 7#jg7 ,jurassic plants from ,caucasia and ,turkestan4 ,mm4 com4 gol4 ,st ,ptersbourg ,n4,s41 ,livr4 #ch4 ---- 7#aj7 ,article 8,gymnosperms10 ,encyclop4 ,brit4 edit4 #aa1 vol4 xii4 ,cambridge4 ---- 7#aa7 ,jurassic plants from ,chinese ,dzungaria4 ,mm4 com4 geol4 ,st ,ptersbourg ,n4,s41 ,livr4 #ge4 ---- 7#aa7 ,the ,jurassic ,flora of ,sutherland4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 xlvii4 pt4 iv4 p4 #fdc4 ---- 7#aa7 ,links with the ,past in the ,plant world4 ,cambridge4 ---- 7#aa7 ,the ,jurassic ,flora of ,yorkshire4 ,the ,naturalist1 ,january1 #aiaa4 ---- 7#ab7 ,mesozoic plants from ,afghanistan and ,afghan-,turkestan4 ,mem4 ,geol4 ,surv4 ,india1 ,pal4 ,ind4 ,n4,s41 vol4 iv4 mem4 ,no4 #d4 ---- 7#ab7 ,a petrified ,williamsonia from ,scotland4 ,phil4 ,trans4 ,r4 ,soc4 vol4 cciii4 p4 #aja4 ---- 7#ab7 ,jurassic plants from ,amurland4 ,mm4 com4 geol4 ,st ,ptersbourg ,n4,s41 ,livr4 #ha4 ---- 7#ac7 ,a contribution to our knowledge of ,wealden ,floras1 with special reference to a collection of plants from ,sussex4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 lxix4 p4 #he4 ---- 7#ad7 ,antarctic ,fossil plants4 ,british ,antarctic 7,terra ,nova7 ,expedit4 #aiaj4 ,nat4 ,hist4 ,report1 ,geology1 vol4 i4 ,no4 #a4 ,london4 ---- 7#ad7 ,wealden ,floras4 ,hastings and ,east ,sussex ,naturalist1 vol4 ii4 ,no4 #c1 p4 #abf4 ,seward1 ,a4 ,c4 and ,n4 ,bancroft4 7#ac7 ,jurassic ,plants from ,cromarty and ,sutherland1 ,scotland4 ,trans4 ,r4 ,soc4 ,edinb4 vol4 xlviii4 pt4 iv4 p4 #hfg4 ,shaw1 ,f4 ,j4 ,f4 7#jh7 ,a contribution to the anatomy of ,ginkgo biloba4 ,new ,phyt4 vol4 vii4 p4 #he4 ---- 7#ji7 ,the seedling structure of ,araucaria ,bidwillii4 ,ann4 ,bot4 vol4 xxiii4 p4 #cba4 ,shaw1 ,w4 ,r4 7#if7 ,contribution to the life-history of ,sequoia sempervirens4 ,bot4 ,gaz4 vol4 xxi4 p4 #ccb4 ,shirley1 ,j4 7#ih7 ,additions to the ,fossil ,flora of ,queensland ,geol4 ,surv4 ,bull4 ,no4 #g4 ,brisbane4 ,siebold1 ,p4 ,f4 von4 7#gj7 ,flora ,japonica1 #ahdb-gj4 ,leipzig4 ,sifton1 ,h4 ,b4 7#ae7 ,on the occurrence and significance of 8bars0 or 8rims0 of ,sanio in the ,cycads4 ,bot4 ,gaz4 vol4 lx4 p4 #djj4 ,sigrianski1 ,a4 7#ac7 ,quelques observations sur l',ephedra helvetica ,mey4 ,univ4 ,genve4 ,facult des sciences1 ,prof4 ,chodat #h1 ,fasc4 x4 ,sinnott1 ,e4 ,w4 7#ji7 ,paracedroxylon1 a new type of ,araucarian wood4 ,rhodora1 vol4 ii4 ,no4 #abi1 p4 #afe4 ---- 7#aa7 ,some features of the anatomy of the foliar bundle4 ,bot4 ,gaz4 vol4 li4 p4 #beh4 ---- 7#ac7 ,the morphology of the reproductive structures in the ,podocarpineae4 ,ann4 ,bot4 vol4 xxvii4 p4 #ci4 ,smith1 ,f4 ,g4 7#jg7 ,morphology of the trunk and development of the microsporangium of ,cycads4 ,bot4 ,gaz4 vol4 xliii4 p4 #ahg4 ,smith1 ,j4 ,e4 7#agig7 ,characters of a new genus of plants named ,salisburia4 ,trans4 ,linn4 ,soc4 vol4 iii4 p4 #ccj4 ,solereder1 ,h4 7#ii7 ,systematische ,anatomie der ,dicotyledonen4 ,stuttgart4 ---- 7#jh7 ,ibid4 ,ergnzungaband4 ,solms-,laubach1 ,graf zu4 7#hd7 ,die ,coniferenformen des ,deutschen ,kupferschiefers und ,zechsteins4 ,pal4 ,abhand4 7,dames and ,kayser71 ,bd4 ii4 ,heft ii4 p4 #ha4 ---- 7#ij7 ,die ,sprossfolge der ,stangeria und der brigen ,cycadeen4 ,bot4 ,zeit4 ,jahrg4 xlviii4 ---- 7#ia7 ,on the ,fructification of ,bennettites ,gibsonianus ,carr4 ,ann4 ,bot4 vol4 v4 p4 #dai4 ---- 7#ib7 ,see ,capellini and ,solms-,laubach4 ---- 7#ic7 ,ueber die in den ,kalksteinen des ,kulm von ,gltzisch-,falkenberg in ,schlesien enthaltenen ,structur bietenden ,pflanzenreste4 ,bot4 ,zeit4 ,jahrg4 li4 p4 #aig4 ---- 7#ig7 ,ueber ,medullosa ,leuckarti4 ,ibid4 ,heft x4 p4 #age4 ---- 7#ii7 ,das ,auftreten und die ,flora der rhtischen ,kohlenschichten von ,la ,ternera 7,chili74 ,neues ,jahrb4 ,min4 ,beilage1 ,bd4 xii4 p4 #eha4 ---- 7#jd7 ,die strukturbietenden ,pflanzengesteine von ,franz ,josefs ,land4 ,k4 ,svensk4 ,vetenskapsakad4 ,hand4 ,bd4 xxxvii4 ,no4 #g1 p4 #c4 ---- 7#jf7 ,die ,bedeutung der ,palaeophytologie fr die systematische ,botanik4 ,mitt4 ,philomath4 ,ges4 in ,elsass-,lothringen1 ,bd4 iii4 p4 #cec4 ---- 7#aj7 ber die in den ,kalksteinen des ,culm von ,gltzisch-,falkenberg in ,schlesien erhaltenen structurbietenden ,pflanzenreste4 ,,iv4 ,vlkelia refracta1 ,steloxylon ,ludwigii4 ,zeitsch4 ,bot4 ,jahrg4 ii4 ,heft viii4 p4 #ebi4 ,south1 ,f4 ,w4 and ,r4 ,h4 ,compton4 7#jh7 ,notes on the anatomy of ,dioon edule ,lind4 ,new ,phyt4 vol4 vii4 p4 #bbb4 ,spiess1 ,karl von4 7#jb7 ,ginkgo1 ,cephalotaxus1 und die ,taxaceen4 ,eine phylogenetische ,studie4 ster4 ,bot4 ,zeitsch4 ,jahrg4 lii4 p4 #dcb4 ---- 7#jc7 ,ibid4 ,jahrg4 liii4 p4 #a4 ,sprecher1 ,a4 7#jg7 ,le ,ginkgo biloba ,l4 ,genve4 ,squinabol1 ,s4 7#ib7 ,contribuzioni alla flora fossile dei terreni terziarii della ,liguria4 ,gnes1 #ahhi-ib4 ,stapf1 ,o4 7#hi7 ,die ,arten der ,gattung ,ephedra4 ,denksch4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 lvi4 ---- 7#if7 ,on the ,flora of ,mount ,kinabalu in ,north ,borneo4 ,trans4 ,linn4 ,soc4 #b1 vol4 iv4 p4 #fi4 ---- 7#ad7 ,encephalartos ,hildebrandtii4 ,bull4 ,miscell4 ,information1 ,r4 ,bot4 ,gard4 ,kew1 ,no4 #aj1 p4 #chf4 ,starr1 ,anna ,m4 7#aj7 ,the microsporophylls of ,ginkgo4 ,bot4 ,gaz4 vol4 xlix4 p4 #ea4 ,staub1 ,m4 7#he7 ,pinus palaeostrobus ,etting4 in der fossilen ,flora ,ungarns4 ,termszetrajzi ,fzetek1 ix4 p4 #dg4 ---- 7#if7 ,die ,fossilen ,ctenis-,arten und ,ctenis hungarica n4 sp4 ,fldtani ,kzlny1 vol4 xxvi4 ,stefani1 ,c4 de4 7#ja7 ,flore ,carbonifere e ,permiane della ,toscana4 ,r4 ,inst4 ,stud4 sup4 pratici e di perfezionamento in ,firenze4 ,stenzel1 ,g4 7#gf7 ,beobachtungen an durchwachsenden ,fichtenzapfen4 ,nov4 ,act4 ,leop4 ,carol4 ,bd4 xxxviii4 ---- 7#hh7 ,see ,goeppert and ,stenzel4 ,sterzel2 ,j4 ,t4 7#hc7 ,ueber ,dicksonia ,pluckeneti 7,schloth474 ,bot4 ,cent4 ,bd4 xiii4 p4 #bhb4 ---- 7#jj7 ,gruppe verkieselter ,araucariten ,stmme4 ,bericht ,naturwiss4 ,ges4 ,chemnitz1 ,bd4 xiv4 ---- 7#jc7 ,ein verkieselter ,riesenbaum aus dem ,rothliegenden von ,chemnitz4 ,ibid4 ,bd4 xv4 p4 #bc4 ---- 7#jg7 ,die ,karbon- und ,rotliegendfloren im ,grossherzogtum ,baden4 ,mitt4 ,badisch4 geol4 ,landes4 ,bd4 v4 ,heft ii4 p4 #cdg4 ---- 7#ab7 ,der 8verkieselte ,wald0 im ,garten des ,knig ,albert ,museums und des ,orth-,denkmal in ,chemnitz-,hilbersdorf4 ,bericht ,naturwiss4 ,ges4 ,chemnitz1 ,bd4 xviii4 p4 #ea4 ,stiles1 ,w4 7#jh7 ,the anatomy of ,saxegothaea conspicua ,lind4 ,new ,phyt4 vol4 vii4 p4 #bji4 ---- 7#ab7 ,the ,podocarpeae4 ,ann4 ,bot4 vol4 xxvi4 p4 #ddc4 ,stirling1 ,j4 7#jj7 ,notes on the ,fossil ,flora of ,south ,gippsland ,jurassic beds4 ,rep4 on the ,vict4 coal-fields1 ,no4 #g4 7,dpt4 ,mines1 ,victoria47 ,stokes and ,webb4 7#bd7 ,descriptions of some fossil vegetables of the ,tilgate ,forest in ,sussex4 ,trans4 ,geol4 ,soc4 #b1 vol4 ii4 p4 #dba4 ,stopes1 ,marie ,c4 7#jc7 ,on the leaf of ,cordaites4 ,new ,phyt4 vol4 ii4 p4 #ia4 ---- 7#jd7 ,beitrge zur ,kenntniss der ,fortpflanzungsorgane der ,cycadeen4 ,flora1 ,bd4 xciii4 ,heft iv4 p4 #dce4 ---- 7#je7 ,on the double nature of the ,cycadean integument4 ,ann4 ,bot4 vol4 xix4 p4 #efa4 ---- 7#jg7 ,the ,flora of the ,inferior ,oolite of ,brora 7,sutherland74 ,quart4 ,journ4 ,geol4 ,soc4 vol4 lxiii4 p4 #cge4 ---- 7#aj7 ,adventitious budding and branching in ,cycas4 ,new ,phyt4 vol4 ix4 p4 #bce4 ---- 7#aj7 ,the internal anatomy of ,nilssonia orientalis4 ,ann4 ,bot4 vol4 xxiv4 p4 #chi4 ---- 7#aa7 ,the ,dragon tree of the ,kentish ,rag1 with remarks on the treatment of imperfectly petrified wood4 ,geol4 ,mag4 #e1 vol4 viii4 p4 #ee4 ---- 7#aa7 ,the name of the ,dragon tree4 ,ibid4 p4 #dfh4 ---- 7#aa7 ,a reply to ,prof4 ,jeffrey's article on ,yezonia and ,cryptomeriopsis4 ,ann4 ,bot4 vol4 xxv4 p4 #bfi4 ---- 7#aa7 ,on the true nature of the ,cretaceous plant ,ophioglossum granulatum ,hr4 ,ann4 ,bot4 vol4 xxv4 p4 #ijc4 ---- 7#ad7 ,the 8,fern ,ledges0 ,carboniferous ,flora of ,st ,john1 ,new ,brunswick4 ,dpt4 ,mines1 ,geol4 ,surv41 ,canada1 ,mem4 #da1 ,no4 #ch1 ,geol4 ,ser4 ,ottawa4 ---- 7#ad7 ,a new ,araucarioxylon from ,new ,zealand4 ,ann4 ,bot4 vol4 xxviii4 p4 #cda4 ---- 7#ae7 ,catalogue of the ,mesozoic ,plants in the ,british ,museum 7,nat4 ,hist474 ,the ,cretaceous ,flora4 ,pt4 ii4 ,lower ,greensand 7,aptian7 plants of ,britain4 ,london4 ---- 7#af7 ,an early type of the ,abietineae787 from the ,cretaceous of ,new ,zealand4 ,ann4 ,bot4 vol4 xxx4 p4 #aaa4 ,stopes1 ,m4 ,c4 and ,k4 ,fujii4 7#aj7 ,studies on the structure and affinities of ,cretaceous ,plants4 ,phil4 ,trans4 ,r4 ,soc4 vol4 cci4 p4 #a4 ,stopes1 ,m4 ,c4 and ,e4 ,m4 ,kershaw4 7#aj7 ,the anatomy of ,cretaceous ,pine leaves4 ,ann4 ,bot4 vol4 xxiv4 p4 #cie4 ,stopes1 ,m4 ,c4 and ,d4 ,m4 ,s4 ,watson4 7#jh7 ,the present distribution and origin of the calcareous concretions in coal-seams known as 8coal-balls40 ,phil4 ,trans4 ,r4 ,soc4 vol4 cc4 p4 #afg4 ,strasburger1 ,e4 7#ff7 ,ein ,beitrag zur ,entwickelungsgeschichte der ,spaltffnungen4 ,pringsheim's ,jahrb4 ,bd4 v4 p4 #big4 ---- 7#ia7 ,ueber den ,bau und die ,verrichtungen der ,leitungsbahnen in den ,pflanzen4 ,histol4 ,beit4 ,heft iii4 ,jena4 ,strbing1 ,o4 7#hh7 ,die ,vertheilung der ,spaltffnungen bei den ,coniferen4 7,inaug4 ,diss4 ,univ4 ,knigsberg47 ,stur1 ,d4 7#fh7 ,beitrge zur ,kenntniss der geologischen ,verhltnisse der ,umgegend von ,raibl und ,kaltwasser4 ,jahrb4 ,k4k4 geol4 ,reichs4 ,wien1 ,bd4 xviii4 p4 #ga4 ---- 7#gg7 ,die ,culm ,flora4 ,heft ii4 ,wien4 ,suzuki1 ,y4 7#aj7 ,on the structure and affinities of two new ,conifers and a new fungus from the ,upper ,cretaceous of ,hokkaido 7,yezo74 ,bot4 ,mag4 ,tokyo1 vol4 xxiv4 ,no4 #bhd1 p4 #ahc4 ,sykes1 ,m4 ,g4 7#aj7 7,see also ,thoday1 ,m4 ,g47 ,the anatomy of ,welwitschia mirabilis ,hook4 f4 in the seedling and adult stages4 ,trans4 ,linn4 ,soc4 vol4 vii4 pt4 ii4 p4 #cbg4 ---- 7#aj7 ,the anatomy and morphology of the leaves and inflorescences of ,welwitschia mirabilis4 ,phil4 ,trans4 ,r4 ,soc4 vol4 cci4 p4 #agi4 ,takeda1 ,h4 7#ac7 ,a theory of transfusion-tissue4 ,ann4 ,bot4 vol4 xxvii4 p4 #cei4 ---- 7#ac7 ,some points in the anatomy of the leaf of ,welwitschia mirabilis4 ,ibid4 vol4 xxvii4 p4 #cdg4 ,tate1 ,r4 7#fg74 ,on the secondary fossils from ,s4 ,africa4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 xxiii4 p4 #acj4 ,tenison ,woods1 ,j4 ,e4 7#hc7 ,on a species of ,brachyphyllum from ,mesozoic coal beds1 ,ipswich1 ,queensland4 ,proc4 ,linn4 ,soc4 ,n4,s4,w4 vol4 vii4 p4 #fei4 ,thibout1 ,e4 7#if7 ,recherches sur l'appareil mle des ,gymnospermes4 ,lille4 ,thiselton-,dyer1 ,w4 ,t4 7#gb7 ,on some ,coniferous remains from the ,lithographic stone of ,solenhofen4 ,geol4 ,mag4 vol4 ix4 p4 #a4 ---- 7#ja7 ,the carpophyll of ,encephalartos4 ,ann4 ,bot4 vol4 xv4 p4 #edh4 ---- 7#ja7 ,persistence of the leaf-traces in ,araucaria4 ,ibid4 vol4 xv4 p4 #edg4 ---- 7#jb7 ,enumeration of the plants known from ,china proper1 ,formosa1 etc4 ,cycadaceae4 ,journ4 ,linn4 ,soc4 vol4 xxvi4 p4 #eei4 ,thoday1 ,mary ,g4 7,sykes1 ,m4 ,g474 7#aa7 ,the female inflorescence and ovules of ,gnetum africanum1 with notes on ,g4 secundum4 ,ann4 ,bot4 vol4 xxv4 p4 #aaja4 ,thoday1 ,m4 ,g4 and ,emily ,m4 ,berridge4 7#ab7 ,the anatomy and morphology of the ,inflorescences and flowers of ,ephedra4 ,ann4 ,bot4 vol4 xxvi4 p4 #iec4 ,thomas1 ,f4 7#ff7 ,zur vergleichenden ,anatomie der ,coniferen-,laubbltter4 ,pringsheim's ,jahrb4 ,bd4 iv4 p4 #bc4 ,thomas1 ,h4 ,hamshaw4 7#aa7 ,the ,jurassic ,flora of ,kamenka in the district of ,isium4 ,mm4 com4 gol4 ,st4 ,ptersbourg ,n4,s41 ,livr4 #ga4 ---- 7#ab7 ,note on the occurrence of ,whittleseya elegans ,newb4 in ,britain4 ,palaeobot4 ,zeitsch4 ,bd4 i4 ,heft i4 p4 #df4 ---- 7#ac7 ,on some new and rare ,jurassic plants from ,yorkshire3 ,eretmophyllum1 a new type of ,ginkgoalean leaf4 ,proc4 ,camb4 ,phil4 ,soc4 vol4 xvii4 pt4 iii4 p4 #bef4 ---- 7#ac7 ,the ,fossil ,flora of the ,cleveland district of ,yorkshire4 ,i4 ,the ,flora of the ,marske quarry4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 lxix4 p4 #bbc4 ---- 7#ae7 ,on some new and rare ,jurassic plants from ,yorkshire3 ,the male flower of ,williamsonia gigas4 ,proc4 ,camb4 ,phil4 ,soc4 vol4 xviii4 pt4 iii4 p4 #aje4 ---- 7#ae7 ,on ,williamsoniella1 a ,new ,type of ,bennettitalean ,flower4 ,phil4 ,trans4 ,r4 ,soc4 vol4 #bjg1 p4 #aac4 ,thomas1 ,h4 ,h4 and ,nellie ,bancroft4 7#ac7 ,on the cuticles of some recent and fossil ,cycadean fronds4 ,trans4 ,linn4 ,soc4 vol4 viii4 pt4 v4 p4 #aee4 ,thompson1 ,w4 ,p4 7#aj7 ,the origin of ray-tracheids in the ,coniferae4 ,bot4 ,gaz4 vol4 l4 p4 #aja4 ---- 7#ab7 ,ray-tracheids in ,abies4 ,ibid4 vol4 liii4 p4 #ec4 ---- 7#ab7 ,the anatomy and relationship of the ,gnetales4 ,i4 ,the genus ,ephedra4 ,ann4 ,bot4 vol4 xxvi4 p4 #ajgg4 ---- 7#ab7 ,the structure of the stomata of certain ,cretaceous ,conifers4 ,bot4 ,gaz4 vol4 liv4 p4 #fc4 ---- 7#af7 ,the ,morphology and ,affinities of ,gnetum4 ,amer4 ,journ4 ,bot4 vol iii4 p4 #ace4 ,thomson1 ,r4 ,b4 7#jg7 ,the ,araucarineae1 a ,protosiphonogamic method of ,fertilisation4 ,science ,n4,s41 vol4 xxv4 p4 #bgb4 ---- 7#ji7 ,on the pollen of ,microcachrys tetragona4 ,bot4 ,gaz4 vol4 xlvii4 p4 #bf4 ---- 7#ac7 ,on the comparative anatomy and affinities of the ,araucarineae4 ,phil4 ,trans4 ,r4 ,soc4 vol4 cciv4 p4 #a4 ---- 7#ad7 ,the spur-shoot of the ,pines4 ,bot4 ,gaz4 vol4 lvii4 p4 #cfb4 ,thomson1 ,r4 ,b4 and ,a4 ,e4 ,allin4 7#ab7 ,do the ,abietineae extend to the ,carboniferous8 ,bot4 ,gaz4 vol4 liii4 p4 #cci4 ,tison1 ,a4 7#ji7 ,sur le ,saxegothaea conspicua ,lind4 ,mm4 soc4 ,linn4 ,normand4 vol4 xxiii4 p4 #aci4 ---- 7#ab7 ,sur la persistance de la nervation dichotomique chez les ,conifres4 ,bull4 soc4 ,linn4 ,normandie vi1 vol4 iv4 p4 #cj4 ---- 7#ab7 ,see ,lignier and ,tison4 ,tupper1 ,w4 ,w4 7#aa7 ,notes on ,ginkgo biloba4 ,bot4 ,gaz4 vol4 li4 p4 #cgd4 ,tuzson1 ,j4 7#ji7 ,monographie der fossilen ,pflanzenreste der ,balatonseegegend4 ,result4 der ,wiss4 ,erforsch4 des ,balatonsees1 ,bd4 i4 ,teil i4 ,budapest4 ---- 7#ji7 ,beitrge zur fossilen ,flora ,ungarns4 ,mitt4 ,jahrb4 ,k4 ,ung4 ,geol4 ,reichs4 ,bd4 xxi4 ,heft viii4 p4 #bcc4 ---- 7#ad7 ,beitrge zur fossilen ,flora ,ungarns4 ,mitt4 ,jahrb4 ,k4 ,ungarisch4 ,geol4 ,reichs4 ,bd4 xxi4 ,heft viii4 ,unger1 ,f4 7#de7 ,synopsis ,plantarum ,fossilium4 ,leipzig4 ---- 7#dg7 ,chloris ,protogaea4 ,leipzig4 ---- 7#di7 ,einige interessante ,pflanzenabdrcke aus der ,k4 ,petrefactensammlung in ,mnchen4 ,bot4 ,zeit4 p4 #cde4 ---- 7#ea7 ,die ,fossile ,flora von ,sotzka4 ,denksch4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 ii4 ,abt4 ii4 p4 #aca4 ---- 7#eb7 ,ueber einige fossile ,pflanzen aus den lithographischen ,schiefer von ,solenhofen4 ,palaeontograph4 ,bd4 ii4 p4 #bea4 ---- 7#eb7 ,iconographia plantarum fossilium4 ,abbildungen und ,beschreibungen fossiler ,pflanzen4 ,denksch4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 iv4 p4 #gc4 ---- 7#ed7 ,zur ,flora des ,cypridinenschiefers4 ,sitzber4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 xii4 p4 #eie4 ---- 7#ed7 ,jurassische ,pflanzenreste4 ,palaeontograph4 ,bd4 iv4 p4 #ci4 ---- 7#ei7 ,der versteinerte ,wald bei ,cairo4 ,sitzber4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 xxxiii4 p4 #bji4 ---- 7#fg7 ,die fossile ,flora von ,kumi4 ,denksch4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 xxvii4 p4 #bg4 ,veitch's ,manual of the ,conifers4 7#jj7 ,london4 ,velenovsk1 ,j4 7#ha7 ,die ,flora aus den ,ausgebrannten ,tertiren ,letten von ,vrovic bei ,laun4 ,abh4 bhm4 ,ges4 vi1 ,bd4 ii4 ---- 7#hg7 ,neue ,beitrge zur ,kenntniss der ,pflanzen des bhmischen ,cenomans4 ,sitzber4 ,k4 bhm4 ,ges4 ,wiss4 ,jahrg4 #ahhf1 p4 #fcc4 ---- 7#hh7 ,ueber einige neue ,pflanzenformen der bhmischen ,kreideformation4 ,ibid4 ,jahrg4 #ahhg4 ---- 7#hi7 ,kvtena eskho ,cenomanu4 ,abh4 ,k4 bhm4 ,ges4 ,wiss4 vii1 ,bd4 iii4 ---- 7#jg7 ,vergleichende ,morphologie der ,pflanzen4 ,teil ii4 ,prag4 ,vernon1 ,r4 ,d4 7#ab7 ,on the geology and palaeontology of the ,warwickshire coalfield4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 lxviii4 p4 #ehg4 ,vetters1 ,k4 ,l4 7#hd7 ,die ,blattstiele der ,cycadeen4 7,inaug4 ,diss47 ,leipzig4 ,vierhapper1 ,f4 7#aj7 ,entwurf eines neuen ,systems der ,coniferen4 ,jena4 ,ward1 ,l4 ,f4 7#he7 ,synopsis of the ,laramie group4 #fth ,ann4 ,rep4 ,u4 ,s4 ,geol4 ,surv4 ---- 7#hg7 ,types of the ,laramie ,flora4 ,bull4 ,u4 ,s4 ,geol4 ,surv4 xxxvii4 ---- 7#hh7 ,the geographical distribution of ,fossil ,plants4 #hth ,ann4 ,rep4 ,u4 ,s4 ,geol4 ,surv4 7#ahhg-hh74 ---- 7#id7 ,fossil ,cycadean trunks of ,north ,america1 with a revision of the genus ,cycadeoidea ,buckland4 ,proc4 ,biol4 ,soc4 ,washington1 vol4 ix4 p4 #ge4 ---- 7#id7 ,recent discoveries of ,cycadean trunks in the ,potomac formation of ,maryland4 ,bull4 ,torrey ,bot4 ,club1 vol4 xxi4 ,no4 vii4 p4 #bia4 ---- 7#id7 ,the ,cretaceous ,rim of the ,black ,hills4 ,journ4 ,geol4 vol4 ii4 ,no4 iii4 p4 #bej4 ---- 7#if7 ,some analogies in the ,lower ,cretaceous of ,europe and ,america4 #afth ,ann4 ,rep4 ,u4 ,s4 ,geol4 ,surv4 ---- 7#ih7 ,descriptions of the species of ,cycadeoidea or fossil ,cycadean trunks thus far determined from the ,lower ,cretaceous rim of the ,black ,hills4 ,proc4 ,u4 ,s4 ,nat4 ,mus4 vol4 xxi4 p4 #ba4 ---- 7#jj7 ,elaboration of the ,fossil ,cycads in the ,yale ,museum4 ,amer4 ,journ4 ,sci4 vol4 x4 p4 #cbg4 ---- 7#jj7 ,description of a new genus and #bj new species of fossil ,cycadean trunks from the ,jurassic of ,wyoming4 ,proc4 ,washington ,acad4 ,sci4 vol4 i4 p4 #bec4 ---- 7#jj7 ,report on the petrified forests of ,arizona4 ,depart4 of the ,interior1 ,washington4 ---- 7#jd7 ,a famous fossil ,cycad4 ,amer4 ,journ4 ,sci4 vol4 xviii4 p4 #dj4 ,warming1 ,e4 7#gg7 ,recherches et remarques sur les ,cycades4 ,oversigt ,k4 ,d4 ,vidensk4 ,selsk4 ,forh4 7,copenhagen71 p4 #af4 ,warren1 ,e4 7#ab7 ,on some specimens of fossil woods in the ,natal ,museum4 ,ann4 ,natal ,mus4 vol4 ii4 pt4 iii4 p4 #cde4 ,webber1 ,h4 ,j4 7#ja7 ,spermatogenesis and fecundation of ,zamia4 ,u4 ,s4 ,dpt4 ,agric4 ,bur4 ,plant ,industry1 ,bull4 ,no4 ii4 ,weiss1 ,c4 ,e4 7#gb7 ,fossile ,flora der jngsten ,steinkohlen-formation und des ,rothliegenden im ,saar-,rhein-,gebiet4 ,bonn1 #ahfi-gb4 ---- 7#gd7 ,note in ,zeitsch4 ,deutsch4 ,geol4 ,ges4 ,bd4 xxvi4 p4 #faf4 ---- 7#gi7 ,die ,flora des ,rothliegenden von ,wnschendorf bei ,lauban in ,schlesien4 ,abh4 geol4 ,specialkarte von ,preussen ,bd4 iii4 ,heft i4 p4 #a4 ,weiss1 ,f4 ,e4 7#ab7 ,report of the #hjth meeting 7,portsmouth7 of the ,british ,assoc4 for the ,advancement of ,science1 p4 #eej4 ---- 7#ac7 ,the root-apex and young root of ,lyginodendron4 ,mem4 ,proc4 ,manchester ,lit4 ,phil4 ,soc4 vol4 lvii4 pt4 iii4 ---- 7#ac7 ,a ,tylodendron-like fossil4 ,ibid4 vol4 lvii4 pt4 iii4 ,wernham1 ,h4 ,f4 7#aa7 ,floral ,evolution2 with particular reference to the sympetalous ,dicotyledons4 ,new ,phyt4 vol4 x4 p4 #gc4 ,wettstein1 ,r4 ,v4 7#ij7 ,die ,omorika-,fichte1 ,picea omorica 7,panc474 ,sitzber4 ,k4 ,akad4 ,wiss4 ,wien1 ,bd4 xcviii4 ,abt4 i4 p4 #ejc4 ---- 7#aa7 ,handbuch der systematischen ,botanik4 7,edit4 ii47 ,leipzig4 ,wherry1 ,e4 ,t4 7#ab7 ,silicified wood from the ,triassic of ,pennsylvania4 ,proc4 ,acad4 ,sci4 ,philadelphia1 vol4 lxiv4 pt4 ii4 p4 #cff4 ,white1 ,d4 7#ij7 ,on ,cretaceous ,plants from ,martha's ,vineyard4 ,amer4 ,journ4 ,sci4 vol4 xxxix4 p4 #ic4 ---- 7#ja7 ,the ,canadian species of the genus ,whittleseya and the systematic relations4 ,the ,ottawa ,naturalist1 vol4 xv4 ,no4 iv4 p4 #ih4 ,white1 ,d4 and ,c4 ,schuchert4 7#ih7 ,cretaceous series of the ,west coast of ,greenland4 ,bull4 ,geol4 ,soc4 ,america1 vol4 ix4 p4 #cdc4 ,wieland1 ,g4 ,r4 7#ii7 ,a study of some ,american ,fossil ,cycads4 ,pt4 ii4 ,the ,leaf structure of ,cycadeoidea4 ,amer4 ,journ4 ,sci4 vol4 vii4 p4 #cje4 ---- 7#jb7 ,notes on living ,cycads4 ,i4 ,on the ,zamias of ,florida4 ,ibid4 vol4 xiii4 p4 #cca4 ---- 7#jf7 ,american ,fossil ,cycads4 ,washington4 ---- 7#jh7 ,historic ,fossil ,cycads4 ,amer4 ,journ4 ,sci4 vol4 xxv4 p4 #ic4 ---- 7#jh7 ,two new ,araucarias from the ,western ,cretaceous4 ,geol4 ,surv4 ,south ,dakota4 ---- 7#ji7 ,the ,williamsonias of the ,mixteca ,alta4 ,bot4 ,gaz4 vol4 xlviii4 p4 #dbg4 ---- 7#aa7 ,on the ,williamsonia ,tribe4 ,amer4 ,journ4 ,sci4 vol4 xxxii4 p4 #dcc4 ---- 7#aa7 ,a study of some ,american ,fossil ,cycads4 ,pt4 v4 ,ibid4 vol4 xxxii4 p4 #acc4 ---- 7#ab7 ,ibid4 pt4 vi4 ,on the smaller flower-buds of ,cycadeoidea4 ,ibid4 vol4 xxxiii4 p4 #gc4 ---- 7#ac7 ,the ,liassic ,flora of the ,mixteca ,alta of ,mexico1 its composition1 age1 and source4 ,ibid4 vol4 xxxvi4 p4 #bea4 ---- 7#ad7 ,a study of some ,american ,fossil ,cycads4 ,pt4 vii4 ,further notes on disk structure4 ,ibid4 vol4 xxxviii4 p4 #aag4 ---- 7#af7 ,american ,fossil ,cycads4 ,vol4 ii4 ,taxonomy4 ,washington4 ,wiesner1 ,j4 7#jc7 ,die ,rohstoffe des ,pflanzenreiches4 ,bd4 ii4 ,leipzig4 ,wild1 ,g4 7#jj7 ,on new and interesting features in ,trigonocarpus olivaeformis4 ,trans4 ,manchester ,geol4 ,soc4 vol4 xxvi4 pt4 xv4 p4 #dcd4 ,williamson1 ,w4 ,c4 7#dj7 ,on the ,distribution of ,fossil remains on the ,yorkshire coast from the ,lower ,lias to the ,bath ,oolite inclusive4 ,trans4 ,geol4 ,soc4 #b1 vol4 v4 p4 #bbc4 ---- 7#ea7 ,on the structure and affinities of the plants known as ,sternbergiae4 ,manchester ,lit4 ,phil4 ,soc4 #b1 vol4 ix4 p4 #cdj4 ---- 7#fi7 ,on the structure and affinities of some exogens from the ,coal ,measures4 ,monthly ,micros4 ,journ4 vol4 ii4 p4 #ff4 ---- 7#gj7 ,contributions towards the history of ,zamia gigas ,l4 and ,h4 ,trans4 ,linn4 ,soc4 vol4 xxvi4 p4 #ffc4 ---- 7#gb7 ,notice of further researches among the plants of the ,coal ,measures4 ,proc4 ,r4 ,soc4 vol4 xx4 p4 #dce4 ---- 7#gb7 ,on the structure of the ,dicotyledons of the ,coal ,measures4 ,rep4 #dast meeting 7,edinburgh7 of the ,brit4 ,assoc4 p4 #aaa4 ---- 7#gd7 ,on the ,organisation of the ,fossil ,plants of the ,coal ,measures4 ,,vi4 ,phil4 ,trans4 ,r4 ,soc4 vol4 clxii4 p4 #fge4 ---- 7#gf7 ,on some fossil seeds from the ,lower ,carboniferous beds of ,lancashire4 ,rep4 #deth meeting 7,bristol7 of the ,brit4 ,assoc4 p4 #aei4 ---- 7#hf7 ,on the morphology of ,pinites oblongus4 ,mem4 ,proc4 ,manchester ,lit4 ,phil4 ,soc4 vol4 x4 #c1 p4 #ahi4 ---- 7#hg7 ,on the ,organisation of the ,fossil ,plants of the ,coal ,measures4 ,,xiii4 ,phil4 ,trans4 ,r4 ,soc4 vol4 #agh4 ---- 7#ij7 ,ibid4 ,,xvii4 ,ibid4 vol4 clxxxi4 p4 #hi4 ,wiliamson1 ,w4 ,c4 and ,d4 ,h4 ,scott4 7#id7 ,the root of ,lyginodendron oldhamium ,will4 ,proc4 ,r4 ,soc4 vol4 lvi4 p4 #abh4 ---- 7#ie7 ,further observations on the ,organisation of the ,fossil ,plants of the ,coal ,measures4 ,,iii4 ,lyginodendron and ,heterangium4 ,phil4 ,trans4 ,r4 ,soc4 vol4 clxxxvi4 p4 #gjc4 ,wills1 ,lucy4 7#ad7 ,plant cuticles from the ,coal ,measures4 ,geol4 ,mag4 #f1 vol4 i4 p4 #che4 ,wills1 ,l4 ,t4 7#aj7 ,the fossiliferous ,lower ,keuper rocks of ,worcestershire4 ,proc4 ,geol4 ,assoc4 vol4 xxi4 p4 #bdi4 ,winkler1 ,c4 7#gb7 ,zur ,anatomie von ,araucaria brasiliensis4 ,bot4 ,zeit4 ,jahrg4 xxx4 p4 #eha4 ,witham1 ,h4 7#cj7 ,on the vegetable fossils from ,lennel ,braes near ,coldstream1 upon the banks of the ,tweed in ,berwickshire4 ,phil4 ,mag4 vol4 viii4 p4 #af4 ---- 7#ca7 ,observations on fossil vegetables accompanied by representations of their internal structure as seen through the microscope4 ,edinb4 ,journ4 ,sci4 vol4 v4 p4 #ahc4 ,worsdell1 ,w4 ,c4 7#if7 ,the anatomy of the stem of ,macrozamia compared with that of other genera of ,cycadeae4 ,ann4 ,bot4 vol4 x4 p4 #fja4 ---- 7#ig7 ,on transfusion-tissue1 its origin and function in the leaves of ,gymnospermous plants4 ,trans4 ,linn4 ,soc4 vol4 v4 #b1 p4 #cja4 ---- 7#ih7 ,the vascular structure of the sporophylls of the ,cycadaceae4 ,ann4 ,bot4 vol4 xii4 p4 #bjc4 ---- 7#ih7 ,the comparative anatomy of certain genera of the ,cycadaceae4 ,journ4 ,linn4 ,soc4 vol4 xxxiii4 p4 #dcg4 ---- 7#ii7 ,observations on the vascular system of the female flowers of ,conifers4 ,ann4 ,bot4 vol4 xiii4 p4 #ebg4 ---- 7#jj7 ,the comparative anatomy of certain species of ,encephalartos4 ,trans4 ,linn4 ,soc4 vol4 v4 pt4 xiv4 p4 #dde4 ---- 7#jj7 ,the affinities of the ,mesozoic fossil ,bennettites ,gibsonianus ,carr4 ,ann4 ,bot4 vol4 xiv4 p4 #gag4 ---- 7#ja7 ,contributions to the comparative anatomy of the ,cycadaceae4 ,trans4 ,linn4 ,soc4 vol4 vi4 pt4 ii4 p4 #aji4 ---- 7#ja7 ,the vascular structure of the flowers of the ,gnetaceae4 ,ann4 ,bot4 vol4 xv4 p4 #gff4 ---- 7#jd7 ,the structure and morphology of the ovule4 ,ann4 ,bot4 vol4 xviii4 p4 #eg4 ---- 7#je7 ,fasciation1 its meaning and origin4 ,new ,phyt4 vol4 iv4 p4 #ee4 ---- 7#jf7 ,the structure and origin of the ,cycadaceae4 ,ann4 ,bot4 vol4 xx4 p4 #abi4 ,wright1 ,w4 ,b4 7#ad7 ,the ,quaternary ,ice ,age4 ,london4 ,yabe1 ,h4 7#ac7 ,mesozoische ,pflanzen von ,omoto4 ,sci4 ,rep4 of the ,tokoku ,imp4 ,univ4 7ser4 ii4 ,geol471 ,bd4 i4 ,heft iv4 p4 #eg4 ,yates1 ,j4 7#ee7 ,notice of ,zamia gigas4 ,proc4 ,yorks4 ,phil4 ,soc4 vol4 i4 p4 #cg4 ,yokoyama1 ,m4 7#id7 ,mesozoic plants from ,kozuke1 ,kii1 ,awa1 and ,tosa4 ,journ4 ,coll4 ,sci4 ,imp4 ,univ4 ,japan1 vol4 vii4 pt4 iii4 p4 #bja4 ---- 7#je7 ,mesozoic plants from ,nagato and ,bitchu4 ,ibid4 vol4 xx4 ,young1 ,j4 7#fi7 ,trans4 ,nat4 ,hist4 ,soc4 ,glasgow1 vol4 i4 pl4 iv4 7,no text47 ---- 7#gf7 ,catalogue of the ,western ,scottish fossils4 ,glasgow4 ,young1 ,mary ,s4 7#jg7 ,the male gametophyte of ,dacrydium4 ,bot4 ,gaz4 vol4 xliv4 p4 #ahi4 ---- 7#aj7 ,the morphology of the ,podocarpineae4 ,ibid4 vol4 l4 p4 #ha4 ,zalessky1 ,m4 7#je7 ber ,frchte aus den ,untercarbon-,ablagerungen des ,mstabeckens in ,nord ,russland4 ,bull4 acad4 ,imp4 sci4 ,st4 ,ptersbourg1 tome xxii4 ,no4 iii4 p4 #aac4 ---- 7#je7 ,notiz ber die obercarbonische ,flora des ,steinkohlenreviers von ,jantai in der sdlichen ,mandshurei4 ,verhand4 ,k4 ,russ4 ,min4 ,ges4 ,st4 ,ptersbourg #b1 ,bd4 xlii4 p4 #che4 ---- 7#ji7 ,communication prliminaire sur un nouveau ,dadoxylon provenant du ,dvonien suprieur du bassin du ,donetz4 ,bull4 acad4 ,imp4 sci4 ,st4 ,ptersbourg4 ---- 7#aj7 ,on the discovery of the calcareous concretions known as coal balls in one of the seams of the ,carboniferous strata of the ,donetz basin4 ,ibid4 p4 #dgg4 ---- 7#aa7 tude sur l'anatomie du ,dadoxylon ,tchihatcheffi ,goepp4 sp4 ,mm4 com4 gol4 ,st4 ,ptersb4 ,n4,s41 ,livr4 #fh1 p4 #a4 ---- 7#aa7 ,note prliminaire sur le ,coenoxylon ,scotti1 nov4 gen4 et sp4 tudes ,palobotaniques1 pt4 i4 ,st4 ,petersburg4 ---- 7#ab7 ,sur le ,cordaites aequalis ,goepp4 sp4 de ,sibrie et sur son identit avec la ,noeggerathiopsis ,hislopi ,bunb4 sp4 de la ,flore du ,gondwana4 ,mm4 com4 gol4 ,st4 ,ptersb4 ,n4,s41 ,livr4 #hf4 ---- 7#ab7 ,on the impressions of plants from the coal-bearing deposits of ,sudenka1 ,siberia4 ,bull4 soc4 ,natural4 ,orel4 pt4 iv4 ---- 7#ac7 ,flore ,gondwanienne du ,bassin de la ,ptchora4 ,i4 ,rivire ,adzva4 ,bull4 soc4 ,oural4 d'amis des ,sci4 ,nat4 ,ekatrinebourg1 vol4 xxxiii4 ,zang1 ,w4 7#jd7 ,die ,anatomie der ,kiefernadel und ihre ,verwendung zur systematischen ,gliederung der ,gattung ,pinus4 7,diss4 ,inaug47 ,giessen4 ,zeiller1 ,r4 7#gh7 ,sur une nouvelle espce de ,dicranophyllum4 ,bull4 soc4 gol4 ,france #c1 vol4 vi4 p4 #faa4 ---- 7#hj7 ,note sur quelques plantes fossiles du terrain permien de la ,corrze4 ,ibid4 vol4 viii4 #c1 p4 #aif4 ---- 7#if7 ,le ,marquis ,g4 de ,saporta1 sa vie et ses travaux4 ,bull4 soc4 gol4 ,france #c1 vol4 xxiv4 p4 #aig4 ---- 7#jj7 ,sur les vgtaux fossiles recueillis par ,m4 ,villiaume dans les gtes charbonneux du ,nord-ouest de ,madagascar4 ,compt4 ,rend4 ,jun4 #e4 ---- 7#jb7 ,nouvelles observations sur la flore fossile du bassin de ,kousnetzk 7,sibrie74 ,ibid4 tome cxxxiv4 p4 #hhg4 ---- 7#je7 ,sur les plantes ,rhtiennes de la ,perse recueillies par ,m4 ,j4 de ,morgan4 ,bull4 soc4 gol4 ,france #d1 tome v4 p4 #aij4 ---- 7#je7 ,sur quelques empreintes vgtales de la formation charbonneuse supracrtace des ,balkans4 ,ann4 ,mines4 ---- 7#jh7 ,see ,douvill and ,zeiller4 ---- 7#aa7 ,note sur quelques vgtaux infraliasiques des environs de ,niort4 ,bull4 soc4 gol4 ,france #d1 tome xi4 p4 #cba4 ---- 7#aa7 ,sur une flore triasique dcouverte ,madagascar4 ,compt4 ,rend4 vol4 cliii4 p4 #bcj4 ---- 7#ab7 ,sur quelques vgtaux fossiles de la ,grande ,oolite de ,marquise4 ,bull4 soc4 acad4 ,boulogne-sur-mer1 tome ix4 p4 #e4 ---- 7,n4,d47 ,see ,malloizel and ,zeiller4 ,zeiller1 ,r4 and ,p4 ,fliche4 7#jd7 ,dcouverte de strobiles de ,sequoia et de ,pin dans le ,portlandien des environs de ,boulogne-sur-mer4 ,compt4 ,rend4 tome cxxxvii4 p4 #ajbj4 ,zeiller1 ,r4 and ,l4 ,m4 ,vidal4 7#jb7 ,sobre algunas impresiones vegetales del ,kimeridgense de ,santa ,mara de ,mey4 ,mem4 ,real ,acad4 ,cienc4 y ,artes ,barcelona1 vol4 iv4 ,no4 #bf4 ,zigno1 ,a4 de4 7#ec7 ,dcouverte d'une flore ,jurassique analogue celle de ,scarborough dans les couches oolitiques des ,alpes ,vnitiennes4 ,bull4 soc4 gol4 ,france #b1 vol4 x4 p4 #bfh4 ---- 7#gc-he7 ,flora fossilis formationis ,oolithicae4 ,vol4 ii4 ,padua1 #ahgc-he4 ,zopf1 ,w4 7#ib7 ,ueber einige niedere ,algenpilze 7,phycomyceten7 und eine neue ,methode ihre ,keime aus dem ,wasser zu isoliren4 ,abh4 ,naturforsch4 ,ges4 ,halle1 ,bd4 xvii4 p4 #gi4 ,,erratum ,for ,elwes1 ,h4 ,j4 and ,a4 ,henry 7#fj7 read 7#jf7 ,,index ,abies magnifica #ge ,acanthocarpus #cje ,a4 xanthioides #cje ,acrostichum crinitum #efh ,adiantides #agc ,adiantites #agc ,a4 bellidulus #agc1 #agd1 #cjg ,aetheotesta #cjd1 #cai1 #cca1 #ccb ,a4 elliptica #ach1 #ccj-ccb ,a4 subglobosa #cca ,agathis #bba1 #bbb1 #bej1 #bhc ,a4 australis #bba ,a4 macrophyllus #bba ,a4 vitiensis #bba ,alethopteris #hf1 #hi1 #ic1 #ajf1 #aji1 #aaa1 #aac1 #aae1 #cbi ,a4 aquilina #ajh ,a4 decurrens #ie ,a4 ,grandini #ajh1 #aag1 #add1 #cbe ,a4 lonchitica #ic1 #ajh1 #aag ,a4 ,serlii #aag ,alnus #bfc ,alstroemeria #cjd ,amphibennettites #dah ,a4 ,bleicheri #dah ,a4 ,renaulti #dah ,amyelon #bfa ,a4 radicans #bfa ,andrews1 ,e4 ,b4 #cje ,androstrobus #dif1 #eje1 #ejf ,a4 ,balduini #eje ,a4 borealis #eje ,a4 ,guerangeri #eje ,a4 ,nathorsti #ejf ,a4 ,scotti #ejf ,a4 sibirica #eje ,a4 zamioides #eje ,aneimia rotundifolia #eci ,aneimites #agc ,a4 fertilis #afi1 #agb ,angiopteris #hg1 #hh1 #ajg ,anomozamites #dfd1 #dfe1 #dgc1 #edh-eea ,a4 ,balli #ehf ,a4 minor #dfe1 #dff ,a4 ,muelleri #eaj1 #eea ,a4 ,schmidtii #egd ,antarcticoxylon #bid-bii ,a4 ,priestleyi #bif-bii ,antherangiopsis rediviva #ejc ,anthodiopsis ,beinertiana #abf ,antholithes liliacea #bfd ,antholithus #bbd1 #bfd ,a4 ,pitcairniae #bfd ,anthrophyopsis #egh1 #egi ,a4 crassinervis #eha ,a4 ,nilssoni #eha ,a4 obovata #eha ,araucaria #bbb1 #bej1 #bea1 #bii ,a4 ,bidwillii #afj ,a4 imbricata #bba ,araucarioxylon #bbd1 #bdh-bej1 #bie ,a4 antiquum #bhe ,a4 australe #bee ,a4 ,beinertianum #aii ,a4 saxonicum #bec ,araucarites #bdj1 #bie1 #ejd ,a4 ,beinertianus #aii ,a4 ,brandlingii #bed ,a4 ,buchianus #baj ,a4 ,oldhami #bde ,a4 ,tchihatcheffi #bdh ,arber1 ,a4 #cjh1 #cde1 #cdf ,arber1 ,e4 ,a4 ,n4 ,passim ,arberia1 #ceb ,archaeopitys #bij ,a4 ,eastmanni #bhh1 #bij ,arctopodium #bjj-bjd1 #bjg ,a4 insigne #bja ,a4 radiatum1 #bja ,artis1 ,f4 ,e41 #bdg ,artisia1 #bdf-bea1 #bec1 #bef ,a4 alternans1 #bdh ,a4 transversa1 #bca1 #bdg ,aspleniopteris ,nilssoni1 #eeh ,asplenium nidus1 #eha ,asterochlaena1 #bjc1 #bje1 #bjg ,a4 kirgisica1 #afe ,asterophyllites1 #bfa ,asteropteris noveboracensis1 #bjc ,asterotheca1 #afh ,attolia speciosa1 #cbg ,aulacopteris1 #ajf ,bambusium1 #bgg ,b4 ,imhofi1 #bhj ,bancroft1 ,n41 #adg1 #ddf1 #dee1 #dhi ,beania1 #ejb1 #ejc1 #eab1 #efh ,b4 ,carruthersi1 #ejb1 #ejc ,b4 gracilis1 #ejb1 #ejc ,bennettites1 #cfg-cga ,b4 dacotensis1 #djc-djh ,b4 ,gibsonianus1 #cgj1 #chf1 #ddh4 ,see also ,cycadeoidea ,gibsoniana ,b4 ,morierei1 #chc1 #chd1 #dbi1 #ddg4 ,see also ,cycadeoidea ,morierei ,b4 portlandicus1 #cfh ,b4 ,saxbyanus1 #chf ,benson1 ,m41 #ed1 #ee1 #fa-fc1 #ga1 #gh-ha1 #abe1 #bbf1 #bbh1 #bge1 #cac ,berger1 ,r41 #cce1 #cda1 #cdb1 #cdi1 #ced ,berry1 ,e4 ,w41 #ege ,bertrand1 ,c4 ,e41 #bad1 #bfg-bfi1 #cjf1 #cdj ,bertrand and ,renault1 #bai ,bertrand1 ,p41 #aaj-aaf1 #adj1 #afe1 #bjj-bje1 #baj1 #cbc1 #cce1 #cdb1 #cdh1 #ceg ,bignonia1 #ccf ,binney1 ,e4 ,w41 #ce1 #cf1 #ci1 #aje ,blastolepis1 #dfj ,b4 acuminata1 #dfj ,b4 falcata1 #dfj ,b4 ,otozamitis1 #dfj ,boissier1 ,e41 #ccf ,bolpopodium1 #dgi ,boroviczia1 #ceh1 #cfj1 #cfc ,b4 ,karpinskii1 #ceh-cfj ,botryoconus1 #bfd1 #bfe ,bowenia1 #d1 #g-i1 #bj1 #bg-bi1 #hg1 #aci1 #cae ,b4 serrulata1 #bg ,b4 spectabilis1 #bj ,b4 spectabilis var4 serrata1 #bj ,bower1 ,f4 ,o41 #ab1 #aif1 #dge ,braun1 ,a41 #ab ,braun1 ,f41 #dge1 #dgg1 #ecg ,brenchley1 ,w4 ,e41 #df1 #dg ,brongniart1 ,a41 ,passim ,brown1 ,r41 #cfh1 #ddh1 #dhj ,buckland1 ,w41 #cfg-cga1 #ddh ,bucklandia1 #cgb1 #cfh1 #djh1 #dbe1 #dbf1 #dgh-dij1 #ebc1 #ebd1 #eca1 #edf ,b4 anomala1 #dha-dhc ,b4 buzzardensis1 #dhf ,b4 indica1 #dhh1 #dhi ,b4 ,mantelli1 #dha ,b4 ,milleriana1 #dhc1 #dhd ,b4 7,fittonia7 ,rigauxi1 #dif ,b4 ,ruffordi1 #dif ,b4 ,saportana1 #dha1 #efi ,b4 7,fittonia7 squamata1 #dhg1 #dif ,b4 squamosa1 #dhg ,b4 ,yatesii1 #dhd-hf ,buckman1 ,j41 #ehh ,bulbopodium1 #cfh1 #cfi1 #dgi ,b4 micromerum1 #dag ,bunbury1 ,c4 ,e4 ,f41 #bdj ,burlingame1 ,l41 #fb1 #cab ,calamarieae1 #aij ,calamopitys1 #aij-aig1 #bjj1 #bdh ,c4 americana1 #aic1 #bjj ,c4 annularis1 #aic1 #aid1 #aih1 #aii ,c4 ,beinertiana1 #aii ,c4 ,saturni1 #aij-aid1 #aih ,calamopteris1 #aij1 #aif ,c4 ,hippocrepis1 #aif ,calamosyrix1 #aij ,calamoxyleae1 #aij ,callipteris1 #aji1 #adb1 #afi ,callixylon1 #bij-bic ,c4 ,trifilievi1 #bia-bic ,calymmatotheca1 #ej1 #ea ,c4 acuta1 #fg ,c4 ,stangeri1 #ej1 #eg ,cambier and ,renier1 #bce ,cardiocarpon1 #bfd ,c4 acutum1 #afi1 #ccg ,c4 anomalum1 #bfd ,c4 barcellosum1 #cea ,c4 ,branneri1 #cdh ,c4 compressum1 #cde ,c4 emarginatum1 #cce1 #chi ,c4 triangulare1 #cch ,cardiocarpum fluitans1 #cdh ,cardiocarpus1 #aga1 #bbd1 #bfe1 #cjb1 #cjc1 #cjg1 #ccc-cde1 #ced ,c4 angustodunensis1 #ccf1 #cda ,c4 areolatus1 #cee ,c4 bicaudata1 #cdh ,c4 7,philocarpus7 bicornutus1 #cdi ,c4 cornutus1 #cej ,c4 drupaceus1 #ccd1 #cch ,c4 drupaceus var4 expansus1 #cci ,c4 indicus1 #adj1 #ada1 #ceb ,c4 ingens1 #cec ,c4 nummularis1 #cci ,c4 sclerotesta1 #ccd1 #cch-cdj1 #cef ,c4 tenuis1 #cci1 #cda ,cardiopteris1 #acf1 #cfj ,carpentier1 ,a41 #fe-fg1 #ha1 #aaj-aac1 #cfe ,carpolites1 #cfc1 #cfd ,c4 sulcatus1 #cfb ,carpolithes1 #cec1 #dig ,c4 alata1 #aah ,c4 conica1 #dih ,c4 granulatus1 #afh ,c4 ,lindleyi1 #bfd ,c4 membranaceus1 #cee ,c4 ,milleri1 #ada ,c4 nitidulus1 #agd ,c4 samaroides1 #cef ,c4 sulcata1 #cei1 #cfb ,carpolithus1 #cbf1 #cfc-cfe1 #dig-ejj ,c4 bivalvis1 #cfe ,c4 ,bucklandi1 #dih ,c4 conicus1 #cfe1 #dih1 #dii ,c4 ,nathorsti1 #ff ,c4 ,pomelii1 #dii ,c4 ,wildii1 #cbe1 #cfe ,carruthers1 ,w41 ,passim ,cassytha1 #cjb ,caulopteris ,adamsi1 #bde ,cephalotaxus1 #cdf ,c4 pedunculata1 #bbb ,ceratozamia1 #f1 #i1 #aj1 #ai1 #bd1 #bh1 #dji1 #ejg1 #ebi ,ceratozamia ,hofmanni1 #ejh ,c4 mexicana1 #af1 #ai1 #ba1 #bb1 #cj1 #bha1 #ecf ,ceropegia peltata1 #bdg ,chamberlain1 ,c4 ,j41 #i1 #bi1 #cia ,cheilanthites elegans1 #gb ,chodat1 ,r41 #ec1 #ed1 #fj1 #aaf1 #afa ,cladoxyleae1 #bjj-baj ,cladoxylon1 #afe1 #bjj-bjg1 #bji1 #baj ,c4 dubium1 #bja1 #bjb ,c4 ,kidstoni1 #adi1 #bje1 #bjf1 #bac ,c4 mirabile1 #bja-bjc1 #bjf ,c4 taeniatum1 #bjb1 #bje ,clathraria1 #dhj1 #dij ,c4 anomala1 #dha1 #dia ,c4 ,lyelli1 #dhj1 #dha ,clathropodium foratum1 #dgi ,c4 sarlatense1 #dgi ,clepsydropsis1 #bjd1 #bje ,codonospermum1 #ach1 #cjd1 #cai1 #ccj1 #cca1 #cfa ,c4 anomalum1 #ccj1 #cca1 #cei ,c4 olivaeforme1 #ccj1 #cca ,codonotheca1 #fg1 #abd-abf1 #abh ,c4 caduca1 #fg1 #abd1 #abe ,c4 pusilla1 #abf ,coenoxylon1 #beb1 #bic1 #bid ,c4 ,scotti1 #bic ,colpospermum1 #cfb1 #cfc ,colpoxylon1 #aji1 #adb-ade1 #bhc ,c4 aeduense1 #aji1 #adb1 #adc ,colymbetes1 #dia-did ,c4 ,edwardsi1 #dia-did ,compsotesta1 #ccc1 #cdg ,c4 ,brongniarti1 #cdg ,compter1 ,g41 #bhj1 #ejj ,condylites1 #dfg ,c4 squamatus1 #dfg ,conites ,bucklandi1 #dhg ,conostoma1 #fd1 #ga1 #gi1 #ha1 #cjc1 #cjf1 #cji1 #cab-cag1 #cbf ,c4 anglo-germanicum1 #cae ,c4 intermedianum1 #gi ,c4 oblongum1 #cjh1 #cac-cae ,c4 ovale1 #gi ,corda1 ,a4 ,j41 #gj1 #bjj1 #bbc1 #bha1 #ejd1 #eje ,cordaianthus1 #adb1 #bbj1 #bbd1 #bfd-bgj ,c4 acicularis1 #bfg ,c4 ,grand',euryi1 #bfh1 #bfi ,c4 ,lacattii1 #bfh ,c4 ,minieri1 #bgi ,c4 ,pitcairniae1 #bcb1 #bcc1 #bff1 #bfg ,c4 ,volkmanni1 #bff1 #bfg ,c4 ,williamsoni1 #bfg1 #bfh ,c4 ,zeilleri1 #bfh ,cordaicarpon1 #ccd ,c4 ,cordai1 #ccd1 #cce ,cordaicarpus1 #bbj1 #bbd1 #bdj1 #bff1 #ccc1 #ccd1 #cce1 #ccg1 #cdb1 #cfd ,c4 ,cordai1 #bcb1 #cej1 #ced1 #cee ,c4 ingens1 #cec ,cordaicladus1 #bbj1 #bbd1 #bde ,cordaioxylon1 #bbj1 #bbc1 #bdh1 #bej ,c4 ,brandlingii1 #bed ,cordaispermum1 #cce ,cordaitales1 #bad-bii ,cordaiteae1 #bai-bhd ,cordaites1 #acg1 #age1 #agf1 #baa1 #bad-bag1 #bai-bhc 7passim71 #bid1 #bii1 #cce ,c4 aequalis1 #bch1 #bci1 #bdc ,c4 australis1 #bdj ,c4 borassifolius1 #bcc1 #bcf1 #bha ,c4 circularis1 #aci1 #bcg1 #bgf ,c4 ,clerci1 #bci1 #bdc ,c4 communis1 #bcc ,c4 crassifolius1 #bbf1 #bcg ,c4 crassus1 #bbf ,c4 ,delvali1 #bce ,c4 ,felicis1 #bbf1 #bbh1 #bcj1 #bge ,c4 gracilis1 #bcf ,c4 grandifolius1 #bce1 #bgf ,c4 7,noeggerathiopsis7 ,hislopi1 #bch-bde1 #bfb ,c4 ,lacoei1 #bcg ,c4 lancifolius1 #bcc ,c4 linearis1 #bcf ,c4 lingulatus1 #bbg1 #bbi1 #bcc-bce ,c4 ,mansfieldi1 #bcb ,c4 microstachys1 #bcf ,c4 ,newberryi1 #bic ,c4 ,ottonis1 #bcb ,c4 palmaeformis1 #bce ,c4 principalis1 #bbf1 #bbi-bcc1 #bff1 #cce ,c4 ,robbii1 #bcc1 #cej ,c4 robustus1 #bbg ,cordaixylon1 #bbc ,cornucarpus1 #ccg ,c4 acutus1 #ccg ,corylus colurna1 #fj ,corypha1 #cha ,cotta1 ,c4 ,b41 #hi1 #if1 #aje ,cri1 ,l41 #bee ,crossotheca1 #eb-ed1 #aac ,c4 ,hoeninghausi1 #ec1 #ed1 #eg ,c4 ,hughesiana1 #eb ,crossozamia1 #cfh1 #ejj1 #ebi ,c4 ,hennocquei1 #ejj ,c4 ,moraeana1 #ejj ,ctenidopsis1 #ehj ,ctenis1 #eaa1 #eab1 #ecb1 #egh-ehc ,c4 asplenioides1 #eha1 #ehb ,c4 falcata1 #ecb1 #ehj1 #ehb ,c4 fallax1 #eha ,c4 hungarica1 #ehj1 #eha ,c4 ,kaneharai1 #ehb ,c4 latifolia1 #ehc ,c4 lunzensis1 #ehj ,c4 orovillensis1 #ehb1 #ehc ,c4 ,potocki1 #ehj1 #ehb-ehd ,c4 remotinervis1 #ehb ,c4 sulcicaulis1 #ehj1 #ehb-ehd1 #ehf1 #ehg ,c4 ,zeyschneri1 #ehj1 #ehb ,ctenophyllum1 #ebh ,c4 angustifolium1 #eef ,c4 grandifolium1 #ehe ,c4 latifolium1 #ehe ,c4 pecten1 #ebh ,c4 ,wardi1 #ehe ,ctenopsis1 #ehe ,ctenopteris1 #eaa1 #eab ,cyathea1 #hh ,cycadales1 #a-cd ,cycadeae1 #h ,cycadella1 #cgd1 #che1 #dag1 #dah ,c4 ramentosa1 #cgi1 #dag ,c4 wyomingensis1 #dah ,cycadeoidea1 #bhb1 #cfg-dag ,c4 buzzardensis1 #cgb1 #dhf ,c4 colossalis1 #chb1 #djh-daj ,c4 dacotensis1 #djc-djh1 #dcd1 #ddi ,c4 ,dartoni1 #chj1 #chd ,c4 etrusca1 #chd1 #dch ,c4 excelsa1 #cgd ,c4 ,gibsoniana1 #cgd1 #cgg1 #chf-cie1 #daa1 #dbj1 #dee1 #def1 #dgj ,c4 gigantea1 #cgb1 #chj1 #daa-daf1 #dgh ,c4 ingens1 #cgh ,c4 ,jenneyana1 #cgb1 #cge1 #dab1 #daf ,c4 ,mc,bridei1 #djc ,c4 ,marshiana1 #cgb1 #djh1 #dji1 #dab ,c4 marylandica1 #cgc ,c4 megalophylla1 #cfg ,c4 micromyela1 #cfi1 #cgd1 #cgf1 #dae1 #dah1 #def1 #dhh ,c4 microphylla1 #cfg1 #cga ,c4 montiana1 #chd ,c4 ,morierei1 #cie-djc1 #def1 #def1 #dgh ,c4 nana1 #cgb ,c4 ,niedwiedzkii1 #dab ,c4 nigra1 #cgd ,c4 ,peachiana1 #chh ,c4 pumila1 #cfi1 #cgb1 #dag ,c4 pygmaea1 #cfh1 #dag ,c4 ,reichenbachiana1 #dji-dab1 #daf ,c4 ,saxbyana1 #chf1 #chh ,c4 ,stilwelli1 #cgd ,c4 superba1 #cgb1 #djh ,c4 ,wielandi1 #cge1 #cgf ,c4 ,yatesii1 #cga1 #cgb1 #dhd ,cycadeomyelon1 #dha1 #dij1 #dia ,c4 ,apperti1 #dij1 #dia ,c4 densicristatum1 #dia ,cycadeorachis1 #eia ,cycadeospermum1 #dif1 #dig ,c4 ,pomelii1 #dii ,cycadeostrobus1 #ejc1 #ejd ,c4 ,brunonis1 #ejd ,c4 elegans1 #ejd ,c4 sphaericus1 #ejd ,c4 truncatus1 #ejd ,cycadinocarpus1 #ccc1 #ccd1 #ccf1 #cda1 #dif1 #dig ,c4 angustodunensia1 #cbf1 #cda ,cycadites1 #cfg1 #cfh1 #ebi1 #eeh-fgb ,c4 ,blandfordianus1 #efa ,c4 confertus1 #efa ,c4 constrictus1 #efa ,c4 gramineus1 #efa ,c4 gyrosus1 #eji1 #efb ,c4 pecten1 #ebj1 #ebb ,c4 pectinoides1 #ebj1 #ebb ,c4 rajmahalensis1 #ega1 #egb ,c4 rectangularis1 #eja1 #efe1 #eff ,c4 ,renaulti1 #eff ,c4 ,roemeri1 #eei ,c4 ,saladini1 #efe ,c4 ,saportae1 #ad1 #eei ,c4 sibiricus1 #efa ,c4 ,steenstrupi1 #eei ,c4 sulcicaulis1 #egh ,c4 taxodinus1 #eji1 #efb ,c4 tenuisectus1 #efc1 #egf ,cycadocephalus1 #dgc-dgg ,c4 ,sewardi1 #dgc-dge ,cycadolepis1 #dhb1 #did-dif ,c4 pilosa1 #did ,c4 villosa1 #did ,cycadorachis1 #eij1 #eia ,c4 abscissa1 #eij ,c4 armata1 #eij ,c4 tuberculata1 #eia ,cycadospadix1 #ada1 #did1 #ejj1 #eja1 #ejd ,c4 ,hennocquei1 #eja ,c4 integer1 #eja ,c4 ,milleryensis1 #cch ,c4 ,pasinianus1 #ejj ,cycadoxylon1 #ahe-ahg ,c4 ,fremyi1 #ahf1 #ahg ,c4 robustum1 #ahf1 #ahg ,cycas1 #d-ac1 #bg1 #bi1 #cd1 #hi1 #id1 #aji1 #aeg1 etc4 ,c4 angulata1 #ba ,c4 ,beddomei1 #ac ,c4 ,cairnsiana1 #ad ,c4 circinalis1 #d1 #ac1 #af1 #bj1 #ba1 #bd1 #be1 #bg ,c4 media1 #cj1 #cc ,c4 ,micholitzii1 #ac1 #ad1 #cc ,c4 pectinata1 #ba1 #bb ,c4 revoluta1 #e1 #g1 #aj1 #bb1 #bg1 #cj ,c4 ,ruiminiana1 #ba1 #bb ,c4 ,rumphii1 #bj ,c4 ,rumphii var4 bifida1 #ac ,c4 siamensis1 #aa1 #ab1 #bg1 #cj1 #afj ,cyclocarpon1 #ccd-ccf1 #cdi ,c4 nummularium1 #cce ,c4 tenue1 #cce ,cyclocarpus1 #cdj1 #cdf ,c4 nummularis1 #cda ,cyclopteris1 #aji1 #acj1 #acf1 #aci1 #bgf1 #dif ,c4 ,jenksiniana1 #dif ,c4 ,klipsteinii1 #edd ,cyclospermum1 #ccc1 #cce1 #cdj1 #cda ,cyclozamia1 #eda ,cylindropodium1 #cfh1 #chf1 #dgh1 #dgi ,dadoxylon1 #bbc1 #bdh-bfj1 #bhi-bie ,d4 australe1 #beb1 #bee1 #bef ,d4 ,brandlingii1 #bea1 #bed1 #bfj ,d4 ,buchianum1 #bbj ,d4 ,kayi1 #bef1 #beh ,d4 materiarum1 #beb1 #bef1 #beg ,d4 medullaris1 #bed ,d4 meridionale1 #bee ,d4 ,newberryi1 #beb ,d4 ,nicoli1 #bee ,d4 nummularium1 #bee ,d4 oldhamium1 #ce1 #ch ,d4 ouangonidium1 #beb ,d4 ,pedroi1 #beb1 #beh1 #bei1 #bge ,d4 permiense1 #bei ,d4 protopityoides1 #bee ,d4 ,spenceri1 #bid ,d4 spetzbergense1 #bfj ,dammara albens1 #bha ,dammarites ,bayeri1 #bhc ,danaea elliptica1 #dge ,davallia aculeata1 #dh ,d4 tenuifolia1 #gg ,dawes1 ,j4 ,s41 #bdg ,dawson1 ,sir ,j4 ,w41 #agc1 #bjc1 #bch1 #bdg1 #bef1 #bgg1 #dfc ,dawson and ,matthew1 #beb ,dawson and ,penhallow1 #aif ,de la ,beche1 #edj ,decagonocarpus1 #ceg ,d4 olivaeformis1 #ceg ,depape and ,carpentier1 #cag ,desmiophyllum1 #bcf1 #bgh ,d4 ,solmsi1 #bhb ,dicksonites1 #afg ,dicranophyllum1 #bdf ,dictyo-,cordaites ,lecoi1 #bch ,dictyopteris1 #edf ,d4 falcata1 #edf ,d4 ,schtzii1 #aac ,dictyothalamus1 #abg ,d4 ,schrollianus1 #aac1 #abg ,dictyoxylon1 #ce1 #cf1 #gb ,d4 ,grievii1 #gb ,d4 oldhamium1 #ch ,d4 radicans1 #bfa ,dictyozamites1 #cgi1 #eaa1 #edf-edh ,d4 falcatus1 #edf ,d4 falcatus var4 distans1 #edg ,d4 falcatus var4 grossinervis1 #edg ,d4 falcatus var4 obtusa1 #edf ,d4 grossinervis1 #edg ,d4 ,hawelli1 #edg1 #edh ,d4 indicus1 #cdf ,d4 ,johnstrupi1 #edg1 #edh ,dioon1 #h1 #i1 #ai1 #bi1 #cj1 #dee ,d4 edule1 #aj1 #ae1 #af1 #ai1 #bg1 #bh1 #cd1 #dfd ,d4 ,purpusii1 #ai ,d4 spinulosum1 #aj1 #ai1 #bc1 #be1 #dag ,dioonites1 #eji1 #ebh1 #eef1 #egb ,d4 ,buchianus1 #ecg ,d4 saxonicus1 #ecg ,d4 spectabilis1 #cfg ,diplopterotesta1 #cfj1 #cfa ,d4 spitzbergensis1 #cei1 #cfj ,diplotesta1 #bfe1 #ccc1 #cdf1 #cdg ,d4 avellana1 #cbb ,d4 ,grand',euryana1 #cbb1 #cdf ,diplotmema1 #gg ,d4 elegans1 #gb ,dolerophylleae1 #acb ,dolerophyllum1 #abd1 #acj-aci1 #bbi1 #bcg1 #bgf1 #cca1 #ccb ,d4 ,berthieri1 #acj1 #acc1 #acf-ach ,d4 fertile1 #acj1 #aca1 #acg1 #ach ,d4 ,goepperti1 #acb-acd1 #acg1 #ach ,d4 pseudopeltatum1 #acf1 #acg ,doleropteris1 #acf ,doleropteroideae1 #acb ,dorety1 ,h4 ,a41 #cj1 #afb ,dorrien-,smith1 ,a4 ,a41 #be ,dory-,cordaites1 #bbd1 #bbg1 #bfe1 #cba ,dory-,cycadolepis1 #did ,dunker1 ,w41 #ebh1 #ebi1 #edd1 #eeh ,duns1 ,j41 #agj ,echinostipes1 #cfh ,edraxylon1 #ch1 #dg ,edwards1 ,w4 ,n41 #cdc ,eichwald1 ,e41 #acb ,elkins and ,wieland1 #bib ,encephalartopsis1 #ejh ,e4 nervosa1 #ejh1 #ehj ,encephalartos1 #f-aj1 #ad1 #bc1 #bh1 #bi1 #cd1 #aeh1 #cgb1 #dhg1 #ejg1 #ejh1 #ebi1 #ehg ,e4 ,altensteinii1 #ad1 #ae1 #ba1 #be1 #bg1 #dab ,e4 ,barteri1 #i1 #bg1 #cj1 #aeh ,e4 caffer1 #ad1 #af ,e4 cretaceus1 #ejh ,e4 denticulatus1 #ejg ,e4 ,fredericki-,guilielmi1 #ad1 #af ,e4 ,ghellinckii1 #aa1 #ad1 #ebi1 #efa ,e4 ,gorciexianus1 #ejh1 #eaj ,e4 ,hildebrandti1 #i ,e4 horridus1 #bg ,e4 ,laurentianus1 #ad ,e4 ,lehmanni1 #ad1 #cbj ,e4 longifolia1 #ad1 #ecf ,e4 villosus1 #bb ,endlicher1 ,s41 #bhe1 #ejc ,endolepis vogesiacus1 #bgh ,eolirion primigenium1 #bhb ,eremopteris1 #afi-agb ,e4 artemisaefolia1 #afi-aga ,e4 ,macconchii1 #agb ,e4 ,neesii1 #afi ,eriotesta1 #cai1 #ccb ,e4 vetutina1 #ccb ,eristophyton1 #aid1 #aig1 #bjj1 #bdh ,e4 ,beinertianum1 #aii1 #bie ,e4 fasciculare1 #aig-aii ,erodium1 #cjd1 #cfd ,ettingshausen1 ,c4 von1 #ebi1 #eea1 #egh1 #eha ,eu-,cordaites1 #bbd ,eu-,ctenis1 #ehj ,euphorbia1 #bdg ,eury-,cycadolepis1 #did-dif ,e4 ,jenkinsiana1 #dif ,euryphyllum1 #bch1 #bde ,eu-,zamites1 #eba1 #eca ,feistmantel1 ,o41 #bdj1 #ddc1 #dde1 #did1 #ead-eag1 #edf1 #efa1 #egb1 #egd1 #egg1 #ehf ,feistmantelia1 #aci1 #dia ,f4 bengalensis1 #aci ,f4 oblonga1 #dia ,felix1 ,j41 #fg1 #gj1 #bbg1 #bej ,fiedler1 ,h41 #abc1 #cce1 #ccf1 #cdi1 #cea ,filicites ,bechei1 #eci1 #edj ,f4 ,bucklandi1 #ecg ,f4 7,sphenopteris7 elegans1 #gb ,f4 ,pluckeneti1 #aff ,fittonia1 #dgh1 #dhg ,f4 ,brongniarti1 #cie ,f4 insignis1 #dhg ,f4 ,rigauxi1 #dhg ,f4 ,ruffordi1 #dhc ,f4 squamata1 #dhg ,flabellaria1 #bbc1 #bcc ,f4 chamaeropifolia1 #bha ,fliche1 ,p41 #bgh1 #bgi1 #bhj1 #cfh1 #ejd ,fontaine1 ,w4 ,m41 #che1 #ejj1 #ejh1 #egh1 #ehj1 #ehb ,fraine1 ,e4 de1 #ie1 #if1 #adi1 #aec1 #aee1 #afa ,friia nobilis1 #eje ,fries1 ,e41 #eff ,fumaria officinalis1 #gb ,gangamopteris1 #beh1 #cch1 #ceb ,g4 ,seixasi1 #cea ,gaudrya1 #cai1 #ccb ,g4 lagenaria1 #ccb ,g4 trivalvis1 #ccb ,geinitz1 ,h4 ,b41 #ccd1 #cfe1 #eeb ,gibbs1 ,l4 ,s41 #fa ,ginkgo biloba1 #g1 #fa1 #fb1 #aai1 #ace1 #aci1 #agc1 #bbb1 #bea1 #bff1 #bid1 #cja1 #cjf1 #cbg1 #ccc1 #cch1 #cci1 #cih1 #dii1 #ejb ,gleichenia1 #gd1 #hh ,glossopteris1 #ada1 #ced ,g4 indica1 #adj ,glossozamites1 #ecj ,g4 brevis1 #ecj ,g4 ,schenkii1 #eda ,g4 ,stoliczanus1 #ecj ,glyptostrobus1 #abg ,gnetales1 #afj ,gnetopsis1 #cjd1 #cji1 #cad1 #cag1 #cah ,g4 anglica1 #cah ,g4 elliptica1 #cad1 #cag1 #cah1 #cei ,gnetum1 #dja ,g4 africanum1 #dja ,g4 ,gnemon1 #fc ,goeppert1 ,h4 ,r41 #if1 #abf1 #abg1 #agc1 #baj1 #bfd1 #bhe1 #bhi1 #bie1 #cje1 #ccf1 #daa1 #dab1 #ebg ,goeppert and ,stenzel1 #hf1 #if1 #ajb1 #afc1 #beb1 #bie ,goldenburg1 ,f41 #bcf ,gomphostrobus1 #bec ,gordon1 ,w4 ,t41 #aha1 #ahc1 #bhh1 #cab ,gothan1 ,w41 #ea1 #bdh-beb ,gourlie1 ,w41 #cf1 #cg ,grand',eury1 ,c41 ,passim ,grieve1 ,g41 #gb ,griffith1 ,w41 #bh1 #cjb ,guilelmites1 #cfe ,halle1 ,t4 ,g41 #bhj1 #ddc1 #deg1 #dgc1 #eag1 #eah1 #eba1 #ebb1 #ebg1 #edj1 #edg1 #eej1 #efc1 #efe1 #ege ,haplocalamus1 #aij ,heer1 ,o41 #agd1 #bhj1 #ccf1 #ceh1 #cfj1 #dfb1 #ebj1 #ebe1 #ecj1 #eda1 #edi1 #efc ,helmacher1 ,r41 #cdi ,hemingway1 ,w41 #id1 #cag ,hemitelia1 #dh ,heterangium1 #ea1 #gj-he1 #hf-id1 #ih1 #aji1 #aef1 #aeg1 #afb1 #afh1 #agi-ahc1 #aic1 #aid1 #bad1 #cji1 #cab1 #caf ,h4 alatum1 #hd ,h4 ,andrei1 #hd ,h4 bibractense1 #hd ,h4 bohemicum1 #hd ,h4 cylindricum1 #hc ,h4 ,duchartrei1 #hc ,h4 ,grievii1 #ga-gc1 #gi-hb ,h4 hibernicum1 #hd ,h4 ,lomaxi1 #gb1 #hc ,h4 minimum1 #hc ,h4 paradoxum1 #gb ,h4 polystichum1 #hd ,h4 punctatum1 #hd ,h4 ,renaulti1 #hd ,h4 ,sturi1 #hd1 #ahc ,h4 tiliaeoidea1 #ga1 #ha-hd ,hexagonocarpus1 #aaf1 #cjc1 #cbb1 #cbc1 #cef ,h4 crassus1 #cef ,h4 ,hookeri1 #ceg ,h4 ,noeggerathi1 #cei ,hexapterospermum1 #aaf1 #aai1 #adj1 #cai1 #cba-cbc1 #cdh1 #cef ,h4 modestae1 #ceg ,h4 ,noeggerathii1 #cbb1 #ceg ,h4 pachypterum1 #cba ,h4 stenopterum1 #cba1 #cbb ,hick1 ,t41 #fg ,hierogramma1 #bjj-bjd ,h4 mysticum1 #bja ,hisingera1 #efi ,holcospermum1 #cdc1 #cfa-cfc ,h4 dubium1 #cfc ,h4 sulcatum1 #ceg1 #cei1 #cfa-cfc ,holden1 ,h4 ,s41 #aji ,holden1 ,r41 #bdc1 #eei1 #efj1 #efc1 #efe ,hollick1 ,a41 #dfa ,hollick and ,jeffrey1 #dia ,hooker1 ,sir ,j41 #aj1 #fj ,hooker and ,binney1 #aah1 #cja ,howse1 ,r41 #agj1 #bcb ,hysterites ,cordaitis1 #bcc ,iodes1 #df ,johnson1 ,t41 #ea1 #eb1 #hd ,jordania1 #ccd1 #ccf ,j4 bignonioides1 #ccf1 #cea ,j4 moravica1 #cdg ,juglans1 #bbb ,j4 regia1 #bdf ,kaloxylon1 #fg ,k4 ,hookeri1 #ch1 #fg ,kalymma1 #aij1 #aib1 #aid-aif ,k4 grandis1 #aib1 #aie1 #aif ,k4 striata1 #aif ,karsten1 ,g41 #cj ,kershaw1 ,e4 ,m41 #bh1 #fa ,kidston1 ,r41 #ea-ec1 #ef1 #aaj1 #aab1 #afh ,kidston and ,gwynne-,vaughan1 #ahe ,klein1 ,l41 #ade ,knorria taxina1 #bcb ,kosmovsky1 ,c41 #bch ,krammera1 #bgg1 #bha ,k4 mirabilis1 #bhj ,krasser1 ,f41 #dbj1 #eec1 #egf1 #ehj ,kraus1 ,g41 #bh1 #baj1 #bie ,kubart1 ,b41 #gj1 #ga1 #hd1 #ahc ,kurtz1 ,f41 #ehi ,kutorga1 ,s41 #acb ,lagenidium1 #fb ,lagenospermum1 #fd-ff1 #agd1 #cji ,l4 ,arberi1 #agc1 #cjg ,l4 glandiforme1 #cfj ,l4 nitidulum1 #agd ,l4 oblongum1 #fe1 #ff ,l4 ,sinclairi1 #eg1 #fd1 #ff1 #ha ,lagenostoma1 #ee-ff1 #ga1 #ha1 #aaf1 #abb1 #abe1 #afj1 #agc1 #cjc1 #cjg-cag1 #cbe1 #cbf1 #cbi1 #dig ,l4 ,kidstoni1 #fd ,l4 ,lomaxi1 #ea1 #ee-fb1 #caa ,l4 oblonga1 #fe ,l4 ovoides1 #ee1 #fb-fd1 #caa ,l4 physoides1 #fb1 #cja ,l4 ,sinclairi1 #fd1 #fe ,l4 urceolaris1 #fe ,leckenby1 ,j41 #dba ,lepidanthium1 #dgg ,lepidocaryon1 #bfe1 #ccc1 #cdf1 #cdg ,l4 avellana1 #cdf ,lepidodendron1 #abe1 #bab1 #bga ,leslie1 ,t4 ,n41 #bdb1 #bef ,lesquereux1 ,l41 #aaj1 #abc1 #aca1 #aef1 #bcb1 #bce1 #cje1 #cbf ,leuthardt1 ,f41 #bhj1 #eej1 #eec ,lignier1 ,o41 #cd1 #fc1 #bag1 #bbi1 #bdg1 #chf1 #dae1 #dbh1 #dcb-dcd1 #dee ,lindley and ,hutton1 ,passim ,linnaeus1 #cfc1 #cfd ,linopteris1 #hf1 #aji1 #aac ,l4 obliqua1 #aaa1 #aac ,lobelia ,rhynchopetalum1 #ab ,loddiges1 ,c41 #cfh ,lomax1 ,j41 #df1 #ij ,lotsy1 ,j41 #hf1 #aag ,lycostrobus1 #ejf ,lyginodendron1 #cf ,l4 anomalum1 #bhi ,l4 ,landsburgii1 #cf1 #cg ,l4 oldhamium1 #ch1 #gj4 ,see also ,lyginopteris oldhamia ,l4 robustum1 #ahg ,l4 ,sverdrupi1 #ch ,lyginopterideae1 #ce-he1 #hi1 #afb ,lyginopteris1 #ce-gj1 #gd-gh1 #hd1 #hf-id1 #ih1 #aji1 #ahf1 #ahi-aia1 #aid1 #aih1 #bad1 #bgc1 #bic1 #bie1 #cji1 #caf1 #cfi ,l4 lacunosum1 #gj ,l4 oldhamia1 #ch-ea1 #ef1 #gb ,l4 tristichum1 #gj ,lygodium1 #hh1 #ahj ,mc,bride1 ,t4 ,h41 #djc ,mc,coy1 ,sir ,f41 #bdj ,mc,lean1 ,r4 ,c41 #ei ,macropterygium1 #eed ,macrozamia1 #g1 #i1 #aj1 #ai1 #bd1 #bh1 #bi1 #ajj1 #aeg1 #aeh1 #cia1 #ebi1 #eca ,m4 ,denisoni1 #af1 #bh ,m4 ,fraseri1 #af1 #bh1 #dii ,m4 gibba1 #ejd ,m4 heteromera1 #ai1 #bg1 #cc ,m4 ,macleayi1 #ecf ,m4 ,moorei1 #f ,m4 ,preissii1 #bc ,m4 spiralis1 #ai ,malacotesta1 #cfc ,m4 oblonga1 #cfc ,manoxylic1 #g ,mantell1 ,g41 #dgh1 #dhj1 #dha ,mantellia1 #cfg1 #cfh ,m4 nidiformis1 #cfg ,marattia1 #ajg ,mariopteris1 #aaa ,marsh1 ,a4 ,s41 #che ,masculostrobus1 #eje ,maslen1 ,a4 ,j41 #bga ,matonia1 #hh1 #aij ,matte1 ,h41 #cj1 #aei1 #afj ,medullosa1 #hf-aaj1 #aai1 #add1 #adi-aeg1 #afa1 #afd1 #afe1 #ahc1 #aij1 #aif1 #bjg1 #bji1 #cai ,m4 anglica1 #hg-ih1 #ajb1 #aje1 #ajg1 #ajh1 #ade-aeh1 #afa1 #ahj1 #bai ,m4 centrofilis1 #ie-ig1 #aeg ,m4 elegans1 #aje-ajg ,m4 gigas1 #ajj ,m4 ,leuckarti1 #hg1 #ajb-aje1 #ajh1 #adb-ade1 #aed-aei1 #afe ,m4 ,ludwigii1 #afc ,m4 porosa1 #hi1 #ib1 #aeg ,m4 pusilla1 #id-if ,m4 ,solmsi1 #ib1 #adh1 #aeg ,m4 ,solmsi var4 gigantea1 #ajj1 #aja1 #aeh ,m4 ,solmsi var4 lignosa1 #ib ,m4 ,solmsi var4 typica1 #aja ,m4 stellata1 #hg1 #hi1 #if1 #ig1 #ajj-ajc1 #aeg1 #aeh1 #afd ,m4 stellata var4 corticata1 #ib1 #ii1 #ajj1 #aeh ,m4 stellata var4 gigantea1 #ib1 #ajj ,m4 stellata var4 lignosa1 #ajj ,m4 stellata var4 typica1 #ig-ii ,medulloseae1 #hf-afe ,megadendron saxonicum1 #bec ,megalorhachis1 #bjd ,m4 elliptica1 #bjd ,megalospermum1 #cbf ,megaloxylon1 #age-ahj1 #ahb1 #ahc1 #aih1 #big ,m4 ,scotti1 #age-ahj ,mesopitys1 #bdh1 #bid-bif ,m4 ,tchihatcheffi1 #bic-bif1 #bii ,mesoxylon1 #bad1 #bag1 #bbj1 #bbe1 #bbf1 #bdf1 #bdh1 #bec1 #bef1 #bfb1 #bff1 #bgj-bgf1 #bid1 #bie1 #bii ,m4 ,lomaxi1 #bgd1 #bge1 #big ,m4 poroxyloides1 #bgd1 #bge ,m4 ,sutcliffi1 #bga-bgd ,metacordaites1 #bfj ,m4 ,rigolloti1 #bed1 #bfj ,mettenius1 ,g41 #cj ,microcycas1 #f1 #g1 #aj1 #ai1 #bc1 #cj1 #fb1 #afb1 #afc ,m4 ,calocoma1 #bg ,microspermum1 #cdc1 #cfe ,miller1 ,h4 #ddi1 #ecf1 #ehd ,miquel1 ,f4 ,a4 ,w41 #ebh1 #efi ,mitrospermum1 #cjg1 #ccc1 #ccf1 #cde1 #cdf ,m4 compressum1 #cad1 #cch1 #cde ,mittagia1 #fc1 #fd ,m4 seminiformis1 #fc ,morire1 ,j41 #cfi1 #cie1 #dae ,morris1 ,j41 #bfd1 #eab1 #ead1 #ebh ,mougeot1 ,a41 #ii ,musocarpus1 #cfa ,m4 difformis1 #cfa ,m4 prismaticus1 #cfa ,myelopteris1 #ajf1 #aed ,myeloxylon1 #hi1 #ic1 #if1 #ii1 #aje-ajh1 #aai1 #abc1 #aci1 #add1 #aed1 #aee1 #aif1bjg1 #cbi ,m4 ,landrioti1 #ic1 #ajb1 #aje1 #ajh ,m4 radiatum1 #ajc1 #aje1 #ajg1 #ajh ,m4 topekense1 #ajh ,myrica1 #bfb ,m4 ,gale1 #fa1 #cah ,naiadea obtusa1 #ehh ,nathorst1 ,a4 ,g41 ,passim ,nephrolepis ,duffi1 #edc ,neuropterideae1 #hg ,neuropteridophylla1 #hf ,neuropteris1 #ef1 #hf1 #hi1 #ajf1 #aji-aab1 #aae1 #aag1 #abf1 #acj1 #aci1 #cdb1 #ceg ,n4 auriculata1 #aaf ,n4 ,carpentieri1 #aab ,n4 gigantea1 #aaj-aac1 #aaf1 #adj ,n4 heterophylla1 #aaj1 #aaa1 #aac-aag ,n4 obliqua1 #aae1 #aaf1 #abd ,n4 pseudogigantea1 #aab ,n4 ,schlehani1 #aaf ,neuropterocarpus1 #aaf ,n4 ,kidstoni1 #aad ,neuropteromedullosa1 #aef ,neurospermum1 #aaf1 #cdd ,neurotheca1 #aaj ,newberry1 ,j4 ,s41 #abh1 #aca1 #cbj1 #ejg1 #ehi ,nilssonia1 #eaa1 #eab1 #edh1 #edi1 #eea1 #eee1 #eff-egh ,n4 bohemica1 #egf ,n4 brevis1 #efg-ega ,n4 compta1 #eee1 #efi1 #egc1 #egd1 #egf1 #egh ,n4 densinervis1 #ege ,n4 elongata1 #eff ,n4 ,johnstrupi1 #ege ,n4 mediana1 #eea ,n4 nipponensis1 #egd ,n4 orientalis1 #efh1 #egb1 #ege1 #egf ,n4 ozvana1 #egf ,n4 polymorpha1 #efg-egc ,n4 princeps1 #egf1 #egg ,n4 pterophylloides1 #cfg1 #efg1 #egb1 #egc ,n4 rajmahalensis1 #ega ,n4 saighensis1 #egj ,n4 ,schaumburgensis1 #egh ,n4 ,schmidti1 #egd ,n4 ,sturii1 #egf ,n4 taeniopteroides1 #ege ,n4 tenuicaulis1 #eef1 #egf ,n4 tenuinervis1 #efi1 #ege ,nilssoniales1 #eaa1 #eff-ehg ,nilssoniopteris1 #efi ,niponophyllum1 #bhb1 #bhc ,n4 cordaitiforme1 #bhb ,noeggerathia1 #ehi1 #eij ,n4 crassa1 #bbg ,n4 cyclopteroides1 #acb ,n4 foliosa1 #ehh ,n4 ,goepperti1 #acb ,n4 palmaeformis1 #bce1 #bch ,noeggerathianthus1 #bfd ,noeggerathiopsis1 #bbj1 #bch-bdc ,n4 ,hislopi1 #bch1 #bda1 #bgf1 #bgg4 ,see also ,cordaites 7,noeggerathiopsis7 ,hislopi1 ,odontopteris1 #hf1 #ajf1 #aji ,oldham and ,morris1 #ddc1 #dhh1 #ead1 #efa1 #egb1 #egd1 #egf1 #egg ,oliver1 ,f4 ,w41 #ee1 #fa-fd1 #gi1 #aai1 #abb1 #cja1 #cjf-cji1 #cba-cbf1 #cbi ,oliver and ,salisbury1 #cjh1 #cac1 #cag ,oliver and ,scott1 #ef1 #fj ,oreodoxites ,martianus1 #cch ,osborne1 ,t4 ,g4 ,b41 #bfa1 #bfb ,otopteris mediana1 #eda ,o4 tenuata1 #edc ,otozamites1 #dfj1 #dfg1 #ejj1 #eaa1 #ead1 #eag1 #eba1 #ebb1 #ebh1 #ecj1 #ecg-ede1 #edf1 #ehg1 #ehi ,o4 abbreviatus1 #eba1 #ebb ,o4 angustatus1 #ead-eaf ,o4 ,beani1 #eda-edd1 #ehg1 #ehh ,o4 ,bechei1 #ech-eda1 #edd ,o4 bengalensis1 #edb ,o4 bengalensis var4 obtusa1 #edc ,o4 brevifolius1 #ddg ,o4 ,bucklandi1 #eda ,o4 ,bunburyanus1 #edb1 #edc ,o4 contiguus1 #edc ,o4 decorus1 #edd ,o4 distans1 #eae ,o4 ,feistmanteli1 #eci1 #edc ,o4 giganteus1 #edd ,o4 ,goeppertianus1 #dhc1 #ech1 #edd ,o4 gracilis1 #eae1 #eaf ,o4 graphicus1 #edj ,o4 groenlandica1 #ecg ,o4 ,hennocquei1 #edj ,o4 ,hislopi1 #eae1 #eaf1 #eba1 #ebb ,o4 indosinensis1 #eda ,o4 ,izuimensis1 #edd ,o4 ,klipsteini1 #ecj1 #edc1 #edd ,o4 lagotis1 #edd ,o4 linearis1 #eda1 #edd ,o4 molianus1 #eda ,o4 obtusus1 #ecg-eda ,o4 obtusus var4 ooliticus1 #edj ,o4 oregonensis1 #edd ,o4 ,polakii1 #eda ,o4 tenuissimus1 #edc ,o4 ,terquemi1 #edj ,o4 vicetinus1 #edj ,ottokaria1 #abd1 #aci-ada ,o4 bengalensis1 #aaf1 #aci1 #adj ,pachytesta1 #ij1 #aae-aag1 #add1 #cjd1 #cai1 #cbc-bcf ,p4 gigantea1 #cbc1 #cbe ,p4 incrassata1 #cbd1 #cbe ,palaeanthus problematica1 #dfa ,palaeopitys1 #baj ,p4 ,milleri1 #baj ,palaeospathe aroidea1 #acb ,palaeoxylon1 #ajj1 #bhi ,palaeoxyris1 #dgg ,p4 microrhombea1 #dgg ,palaeozamia1 #ddb1 #ddc1 #eac1 #ead ,p4 acutifolia1 #ead ,p4 affinis1 #ead1 #eae ,p4 bengalensis1 #ead ,p4 cutchensis1 #ead1 #eae ,p4 longifolia1 #bha ,p4 pecten1 #dba ,p4 recta1 #ecd ,p4 rigida1 #ead1 #eae ,p4 ,rubidgei1 #ehe ,palmacites1 #aah ,parapitys1 #bid1 #bie ,p4 ,spenceri1 #bid1 #bie ,parkinson1 ,j41 #cfg ,paullinia1 #hh ,pearson1 ,h4 ,h4 ,w41 #bh1 #djb ,pecopteris ,pluckeneti1 #aff-afh1 #aga1 #cjh ,p4 ,sterzeli1 #afh ,pecopteromedullosa1 #aef ,pelourdea1 #bgg-bha ,p4 hadroclada1 #bhj ,p4 ,imhofi1 #bhj ,p4 keuperiana1 #bhj ,p4 megaphylla1 #bha ,p4 mirabilis1 #bha ,p4 vogesiaca1 #bgh1 #bgi1 #bha ,penhallow1 ,d4 ,p41 #ajh1 #bea ,phillips1 ,j41 #bha1 #ebj1 #ebb1 #eeh1 #egh ,phoenicopsis1 #bcf1 #bgh1 #bhj ,phylladoderma1 #bdd ,p4 ,arberi1 #bdd ,phyllocladus1 #abb ,phyllotaenia1 #bhj ,p4 hadroclada1 #bhj ,p4 longifolia1 #bhj ,physostoma1 #fb1 #fd1 #abe1 #cjd1 #cji-caf1 #cbf1 #cbi1 #cei ,p4 elegans1 #fb1 #cji1 #caa1 #cad ,pilularia1 #eh1 #fd1 #cbg ,pinites1 #ce ,p4 ,brandlingii1 #bed ,p4 ,goepperti1 #baj ,p4 medullaris1 #bhi ,p4 ,withami1 #bhi ,pissadendron1 #bhe ,pitcairnia1 #bfd ,pityeae1 #bhe-bii ,pityoxylon chasense1 #bea ,pitys1 #ahc1 #bhe-bhi1 #bij ,p4 antiqua1 #bhe-bia ,p4 ,dayii1 #bhh ,p4 primaeva1 #bhg-bhi ,p4 ,withami1 #bhf1 #bhi ,plagiozamites1 #ecj1 #ehi1 #eij ,p4 carbonarius1 #eij ,p4 ,planchardi1 #eji1 #ehi1 #eij ,platylepis1 #cfi1 #dae1 #dgh ,p4 micromyela1 #dgi ,platypterygium1 #ehf ,p4 ,balli1 #eee1 #eef ,p4 densinerve1 #ege ,p4 ,rogersianum1 #egf ,platyspermum1 #aad1 #cdc1 #cfb1 #cfc ,p4 sulcatum1 #cfb ,poa-,cordaites1 #bbd1 #bbg1 #bcf1 #bhj1 #bhc ,p4 tenuifolius1 #bcf ,podocarpus1 #fa1 #bfb ,podocarya1 #chf1 #ddi ,podozamites1 #bha1 #ebi1 #ehh ,p4 ,milleri1 #ecf ,p4 ,zitteli1 #ecj ,polylophospermum1 #cai1 #cbb1 #cbi1 #ccj ,p4 stephanense1 #cbb1 #cbi ,polypodioides pecteniformis1 #ebb1 #ebc ,polypodium heracleum1 #ade1 #aij ,p4 irioides1 #eff ,p4 quercifolium1 #ade1 #aij ,polypterocarpus1 #ceg1 #ceh1 #cfa ,p4 anglicus1 #cba1 #cbd1 #ceg ,polypterospermum1 #cai1 #cbc ,p4 ,renaulti1 #cbb1 #cbc ,pomel1 ,a41 #cfh1 #dig1 #ejj1 #ebi1 #eda ,poroxyleae1 #bad-bai ,poroxylon1 #hc1 #adb1 #bad-bai1 #bbf1 #bfb1 #bgj1 #bge1 #bgf1 #bie1 #cdc ,p4 ,boysseti1 #bad1 #bah1 #bai ,p4 ,duchartrei1 #bad ,p4 ,edwardsii1 #baf-bai ,p4 stephanense1 #bag1 #bai ,potoni1 ,h41 #ch1 #aaa1 #aab1 #aff1 #bdi1 #edi1 #eij ,potoniea1 #aac1 #aaf1 #aag1 #abh1 #abi ,p4 adiantiformis1 #aaa1 #aab1 #aca ,prankerd1 ,t4 ,l41 #fb1 #fc ,priestley1 ,r41 #bif ,primula auricula1 #ia ,protocycadaceae1 #afa ,protopityeae1 #baj-bac ,protopitys1 #bjg1 #bji-bac1 #bee ,p4 ,buchiana1 #baj-bac ,psaronius1 #hh1 #afh1 #bec ,pseudoctenis1 #ebh1 #eef1 #ehd-ehg ,p4 ,balli1 #ehf ,p4 crassinervis1 #ehe ,p4 eathiensis1 #ehd1 #ehe ,p4 ensiformis1 #ehe ,p4 ,lanei1 #ehf ,pseudocycas1 #ad1 #eaa1 #eeh-efe ,p4 insignis1 #efj1 #efb1 #efe ,p4 ,roemeri1 #efj1 #efd ,p4 ,saportae1 #efj1 #efc1 #efd ,p4 ,steenstrupi1 #efj1 #efa1 #efc ,psygmophyllum1 #bgf ,p4 ,delvali1 #bce ,p4 flabellatum1 #bch ,p4 majus1 #bce ,pteridotheca ,butterworthi1 #ed ,pterispermostrobus1 #ff1 #fg1 #abf ,p4 bifurcates1 #fe1 #ff1 #abf ,pterophyllum1 #eaa1 #edh-eeh ,p4 aequale1 #eef ,p4 angustifolium1 #egf ,p4 ,bavieri1 #eee ,p4 blechnoides1 #eji1 #eeb ,p4 ,braunianum1 #eed1 #eef1 #eeh ,p4 ,bronni1 #eec1 #eed ,p4 ,buchianum1 #ebi ,p4 ,cambryi1 #eji1 #eeb ,p4 ,carterianum1 #ehf ,p4 concinnum1 #edi ,p4 ,cottaeanum1 #eji1 #eeb ,p4 crassinerve1 #eej ,p4 distans1 #eeg ,p4 ,dunkerianum1 #ebg1 #ebh1 #eeg ,p4 ,fayoli1 #eji1 #eea1 #eeb ,p4 ,footeanum1 #eeg ,p4 ,goeppertianum1 #edd ,p4 gonorrachis1 #eji ,p4 ,grand',euryanum1 #eji1 #eeb ,p4 inconstans1 #eee ,p4 inflexum1 #eji ,p4 ,jaegeri1 #edh-eej1 #eec ,p4 longifolium1 #eec ,p4 ,lyellianum1 #eeg1 #eeh ,p4 majus1 #edh ,p4 marginatum1 #eej ,p4 medianum1 #egf ,p4 minus1 #edh ,p4 ,morrisianum1 #egh1 #ehf ,p4 ,nathorsti1 #eef ,p4 ,nilssoni1 #eea1 #eeg1 #eeh ,p4 oblongifolium1 #ecj ,p4 pecten1 #eab1 #eag ,p4 princeps1 #egc1 #egf1 #ehf ,p4 rigidum1 #ebc ,p4 ,rogersianum1 #eed1 #ege ,p4 saxonicum1 #ecg ,p4 ,schaumburgense1 #egh ,p4 ,schenki1 #eee ,p4 ,tietzei1 #eed1 #eee ,p4 ,williamsonis1 #egc ,pterospermum1 #cdc1 #ceg ,p4 anglicum1 #ceg ,pterozamites1 #ebi ,ptilophyllum1 #cgi1 #eab-ebi1 #eci ,p4 acutifolium1 #ddf1 #eag1 #eba1 #ebb ,p4 acutifolium var4 maximum1 #eae ,p4 ,anderssoni1 #ebe1 #ebg ,p4 antarcticum1 #ebe1 #ebg ,p4 boreale1 #ebe-ebg1 #ecj ,p4 cutchense1 #dgh1 #ead-eag1 #eba1 #ebb1 #ebd ,p4 cutchense var4 curvifolium1 #eae ,p4 ,dunkerianum1 #ebg ,p4 hirsutum1 #ebj ,p4 pecten1 #dcg-ddj1 #ddc1 #dde1 #eab-ebe ,ptilozamites1 #eaa1 #eab ,ptychotesta1 #cai1 #cba1 #cbb1 #cdh ,p4 pachypterum1 #cbb ,p4 tenuis1 #cba1 #cbb ,ptychoxylon1 #adb1 #ade1 #ahf-aij ,p4 ,levyi1 #ahg-aij ,pychnoxylic1 #g ,pycnophyllum1 #bbc ,rachiopteris aspera1 #dg ,r4 ,williamsoni1 #aed1 #aee ,raciborski1 ,m41 #dab1 #egh1 #eha1 #ehb ,radiculites reticulatus1 #bag ,radiospermum1 #fd ,r4 ornatum1 #cbc 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#ehd ,richter1 ,p4 ,b41 #bjj ,roehl1 von1 #acf ,salisbury1 ,e4 ,j41 #abb1 #cjg1 #cbj ,samaropsis1 #afh-aga1 #bcf1 #bde1 #bfe-bfg1 #cjc1 #ccc-cch1 #cde-ced ,s4 acuta1 #afg-aga ,s4 alata1 #cea ,s4 ,baileyi1 #cea ,s4 barcellosus1 #cej1 #cea ,s4 bicaudata1 #cdh1 #cej ,s4 bignonioides1 #cej ,s4 ,crampii1 #cdi ,s4 emarginata1 #ccg1 #cdi1 #cej ,s4 fluitans1 #adb1 #cch1 #cdh1 #cej ,s4 indica1 #ceb1 #cec ,s4 ,leslii1 #ceb1 #cec ,s4 marginata1 #ccg ,s4 ,milleri1 #cec ,s4 moravica1 #cdi1 #ceb ,s4 ,newberryi1 #cej ,s4 ,pitcairniae1 #bff ,s4 ,seixasi1 #cej1 #cea ,s4 spitzbergensis1 #cfj ,s4 ulmiformis1 #ccf ,saporta1 ,g4 de1 #cfh1 #cfi1 #dbb1 #dbi1 #dcd1 #ddi1 #dgg-dgi1 #did1 #dii1 #ejj1 #ehi ,saporta and ,marion1 #acb1 #acg1 #ach1 #cag1 #cie1 #eja1 #eje ,sarcotaxus1 #bfe ,s4 angulosus1 #cdg ,s4 avellana1 #cdf ,s4 olivaeformis1 #cdg ,schenk1 ,a41 #ig1 #afd1 #bhb1 #ccf1 #ebi1 #eej1 #eed1 #eee1 #efh1 #egh1 #eha ,schimper1 ,w4 ,p41 #abg1 #dgg1 #ejj1 #eja1 #eje1 #ecj1 #eed ,schimper and ,mougeot1 #bgh ,schizodendron1 #bej ,schizopodium1 #cfi ,s4 ,renaulti1 #cfi ,schizospermum1 #cai ,schizoxylon1 #bjj1 #bjc ,s4 taeniatum1 #bja ,schlotheim1 ,e4 ,f4 von1 #aff ,schmaulhausen1 ,j41 #agd1 #bcc1 #bch1 #bdd1 #bde ,schuster1 ,j41 #daa1 #dab1 #dgg ,schtzia1 #abd-abg ,s4 anomala1 #abf1 #abg ,s4 ,bennieana1 #abg ,s4 permiensis1 #abg ,scolopteris1 #afh ,scott1 ,d4 ,h41 ,passim ,scott and ,jeffrey1 #aia1 #aif ,scott and ,maslen1 #aai1 #abb1 #ccj ,scuto-,cordaites1 #bcg ,s4 ,grand',euryi1 #bch ,sellards1 ,e4 ,h41 #abf ,senecio praecox1 #bhg ,senftenbergia1 #fc ,sequoia1 #bag ,serjania1 #hh ,sewardia latifolia1 #ehi1 #eia ,shaw1 ,f4 ,j4 ,f41 #afj ,shirley1 ,j41 #bee ,sigillaria1 #bad ,sigillariopsis1 #bad ,solms-,laubach1 ,graf zu41 ,passim ,sorocladus stellata1 #aaj ,sparganum1 #ic1 #aje1 #ahd1 #aia ,spencer1 ,j41 #bid ,sphaereda paradoxa1 #ejb ,sphaerostoma1 #ga1 #gh-ha1 #cjg1 #cji1 #caf1 #cai ,s4 ovale1 #gi1 #hj1 #cab1 #cac ,sphenophyllum1 #aaj ,sphenopteridophylla1 #hf ,sphenopteris1 #aji ,s4 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#bhd ,t4 ,grand',euryi1 #bhc1 #bhd ,torreya1 #cja1 #cbe1 #cdg ,trigonocarpon1 #aag1 #aah ,trigonocarpus1 #fa1 #ij1 #id1 #aae-abc1 #afb1 #cja1 #cjc1 #cjg1 #caf-cbi1 #cde1 #dii ,t4 actaeonelloides1 #ced ,t4 corrugatus1 #abd ,t4 ,dawesi1 #abc1 #cbj ,t4 ,moyseyi1 #abb ,t4 multicarinatus1 #cbj ,t4 olivaeformis1 #aai ,t4 ,oliveri1 #abb ,t4 ,parkinsoni1 #aah-abc1 #cai-cba1 #cbi ,t4 pusillus1 #abb1 #cai1 #cbj ,t4 rostratum1 #cba ,t4 schizocarpoides1 #cai ,t4 shorensis1 #aba-abd1 #cai1 #cbj ,t4 sporites1 #cbj ,trigonocarpum gloagianum1 #ceh1 #cfj ,tripterospermum1 #aai1 #cba1 #ceh1 #cfi ,t4 ellipticum1 #cba1 #ceg ,tsuga1 #abg1 #cae ,tylodendron1 #bej1 #bec1 #dia ,tyson1 ,p41 #che ,tysonia marylandica1 #che ,ullmannites ,beinertianus1 #aii ,ulospermum1 #dig ,unger1 ,f41 #aij1 #aid1 #aif1 #bjj1 #bja1 #bjc1 #bjd1 #bhe1 #ddi ,vectia1 #dai1 #dbj ,v4 luccombensis1 #dai ,velenovsk1 ,j41 #bha1 #ejd1 #eje ,vlkelia1 #bjh-baj ,v4 refracta1 #bjh1 #bji ,vries1 ,h4 de1 #aj ,walch1 ,j4 ,e4 ,j41 #dig ,walchia1 #bec1 #cch ,ward1 ,l4 ,f41 #cfh1 #cfi1 #che1 #dji1 #dag1 #dia1 #dig1 #ehb ,wardia1 #agb-agd ,w4 fertilis1 #aga1 #agb ,warming1 ,e41 #be ,warren1 ,e41 #bef ,watson1 ,d4 ,m4 ,s41 #fh ,weber and ,sterzel1 #ig1 #ii1 #aja1 #ajd1 #ajh ,weiss1 ,c4 ,e41 #bfd1 #cch ,weiss1 ,f4 ,e41 #ed1 #fh ,welsford1 ,e4 ,j41 #fa ,weltrichia1 #dge-dgg ,w4 ,fabrei1 #dgg ,w4 mirabilis1 #dgf ,w4 oolithica1 #dgg ,welwitschia1 #afj1 #afa1 #ccf1 #chj1 #djc ,wettstein1 ,r4 ,v41 #djc ,white1 ,d41 #afi1 #agb1 #agc1 #aib1 #bdc1 #bee1 #beh1 #bhd1 #cbf ,whittleseya1 #abd-aca ,w4 brevifolia1 #abh ,w4 concinna1 #aca ,w4 elegans1 #abh-aca ,w4 fertilis1 #abi1 #acj ,w4 integrifolia1 #aca ,w4 undulata1 #aca ,wieland1 ,g4 ,r41 ,passim ,wielandia1 #dfc ,wielandiella1 #ded1 #dfc-dfg1 #dgb1 #dgc1 #dgh1 #dha1 #eej ,w4 angustifolia1 #dfd1 #dff1 #dfg1 #dgj ,w4 punctata1 #ddf ,wild1 ,g41 #aai ,williamson1 ,w4 ,c41 ,passim ,williamson and ,scott1 #db-df1 #fg1 #fi1 #gd1 #ge1 #gg ,williamsonia1 #cgb1 #chf1 #dji1 #dab1 #dba-dfc1 #did1 #eaf1 #eag1 #ebj1 #ebd1 #eca-ecd1 #ech1 #edf ,w4 angustifolia1 #dfc ,w4 ,bibbinsi1 #dfb ,w4 bituberculata1 #deg ,w4 ,blandfordi1 #dde1 #ddf1 #eag ,w4 ,bucklandi1 #chf1 #ddh1 #ddi ,w4 ,carruthersi1 #dci1 #ddg1 #ddh ,w4 cretacea1 #dfa1 #dfb ,w4 ,cuauhtemoc1 #ddf ,w4 elongata1 #dfb ,w4 ,forchammeri1 #dfa ,w4 gallinacea1 #dfb ,w4 gigas1 #dba-dcf1 #ddc-ddg1 #dea1 #deg1 #dfj1 #dgb1 #dhc ,w4 hastula1 #dbb ,w4 ,haydeni1 #dfj ,w4 indica1 #ddf ,w4 ,leckenbyi1 #dci1 #ddj1 #ddh1 #dgc ,w4 ,lignieri1 #dgb ,w4 mexicana1 #dei1 #dfj ,w4 microps1 #dde ,w4 minima1 #dfa ,w4 ,morieri1 #cie ,w4 oregonensis1 #dfa ,w4 ,otozamitis1 #dfj ,w4 pecten1 #dbb1 #dbf1 #ddj-ddb1 #dde1 #def ,w4 phoenicopsoides1 #dfb ,w4 problematica1 #dfa1 #dfb ,w4 pyramidalis1 #deg ,w4 recentior1 #dfc ,w4 ,riesii1 #dfa ,w4 scotica1 #cgd1 #cia1 #cif1 #djc1 #dae1 #ddj1 #ddg1 #ddi-def1 #dfe1 #dgh1 #dhi ,w4 setosa1 #dcf1 #ddc-dde ,w4 ,smockii1 #dfa ,williamsonia sp41 #ddc-ddf1 #dfj ,w4 spectabilis1 #dce-ddb1 #deg1 #dde1 #dei1 #dfj1 #dgc1 #dgf ,w4 virginiensis1 #dfb ,w4 whitbiensis1 #dce1 #dch-ddb1 #deg1 #deh1 #dfj ,williamsoniella1 #dcd1 #ded1 #dfg-dgc ,w4 coronata1 #dfg-dgb ,w4 ,lignieri1 #dgb ,wills1 ,l4 ,t41 #bgh ,witham1 ,h41 #ce1 #bed1 #bhe1 #bhi ,worsdell1 ,w4 ,c41 #cj1 #cc1 #cd1 #df1 #aee1 #aei1 #afj1 #afb1 #djc ,xenoxylon phyllocladoides1 #bac ,yabe1 ,h41 #egh ,yates1 ,j41 #dba ,yatesia1 #chf1 #dgh ,y4 crassa1 #dhc ,y4 gracilis1 #dhc ,y4 ,joassiana1 #dhc ,y4 ,morrisii1 #dhd ,y4 vogesiacus1 #bgg1 #bgh1 #dhc ,y4 ,yatesii1 #dhd ,yokoyama1 ,m41 #ecg1 #egh1 #ehb ,young1 ,g41 #dba ,young1 ,j41 #ceh ,yucca1 #bgg ,yuccites1 #bgg1 #bgh ,y4 ,schimperianus1 #bha ,zalessky1 ,m41 #gj1 #aia1 #aid1 #aig1 #aih1 #bch1 #bdc1 #bdd1 #bia-bie1 #ceh1 #cei1 #eij ,zalesskya gracilis1 #ahj ,zamia1 #aa1 #ab1 #af1 #bd1 #cj1 #fb1 #aci1 #ejg ,z4 angustifolia1 #af ,z4 ,brongniarti1 #cie ,z4 crassa1 #ejd ,z4 floridana1 #af1 #bd1 #be ,z4 furfuracea1 #ai ,z4 gigas1 #dba ,z4 ,goldiei1 #ebb ,z4 integrifolia1 #af1 #gf ,z4 linifolia1 #af ,z4 ,loddigesii1 #e1 #af1 #ah ,z4 macrocephala1 #ejc ,z4 muricata1 #ehg ,z4 pectinata1 #ebb ,z4 praecedens1 #eaj ,z4 pseudoparasitica1 #ai ,z4 pumila1 #i ,z4 pygmaea1 #d ,z4 ,skinneri1 #ehg ,z4 ,wallisii1 #af1 #ag ,zamieae1 #h ,zamiophyllum1 #ebi-eca ,zamiopsis1 #eab ,zamiostrobus1 #dif1 #ejc ,z4 ,loppineti1 #ejd ,z4 orientalis1 #ejd ,z4 ,saportana1 #eje ,zamites1 #bha1 #cgh1 #cgi1 #ejg1 #eab1 #eag1 #ebj1 #eba1 #ebe1 #ebg1 #ebi-ecg1 #ehi1 #eij ,z4 ,anderssoni1 #eba ,z4 antarcticus1 #eba1 #ebg ,z4 bohemicus1 #ecd ,z4 borealis1 #eba1 #ebe1 #ecj1 #eca ,z4 brevipennis1 #eba1 #ebe ,z4 ,buchianus1 #eca1 #ece-ecg ,z4 carbonarius1 #eij ,z4 ,carruthersi1 #ece1 #ecf ,z4 claravallensis1 #ecd ,z4 eathiensis1 #ehd ,z4 epibius1 #eaj ,z4 familiaris1 #eje ,z4 ,feneonis1 #ecc ,z4 gigas1 #dbb-dbf1 #ddc1 #eaj1 #eba1 #ecj-ecd ,z4 iburgensis1 #ecd ,z4 ,mantelli1 #ecb ,z4 ,moreaui1 #ecc ,z4 palaeocenicus1 #eaj ,z4 pusillus1 #eba ,z4 recta1 #ecd ,z4 ,renevieri1 #ecc ,z4 ,schmiedelii1 #ecd ,zamites sp41 #ehe ,z4 speciosus1 #eba1 #ebe ,z4 truncatus1 #ecb ,z4 ,zitteli1 #ece ,zeiller1 ,r41 ,passim ,zigno1 ,a4 de1 #bha1 #dfj1 #ehg1 #ehh ,zopf1 ,w41 #fb1 #ech ,,footnotes3 #a ,wieland 7#jf7 p4 #aij4 #b ,botanical ,magazine1 ,tab4 #agda4 #c ,matte 7#jd7 ,pl4 xi4 fig4 #ahe 7,microcycas74 #d ,thibout 7#if74 #e ,thibout 7#if7 ,pl4 iv4 fig4 #c4 ,a branched microstrobilus of a ,macrozamia is exhibited in the ,botanical ,department of the ,british ,museum4 #f ,pearson 7#jf74 #g ,sohns-,laubach 7#ij72 ,south and ,compton 7#jh72 ,smith1 ,f4 ,g4 7#jg74 #h ,chamberlain 7#ac74 #i ,lang 7#ig72 7#jj74 #aj ,chamberlain 7#ji7 p4 #daj4 #aa ,caldwell 7#jg74 #ab ,for figures and references1 see ,coulter and ,chamberlain 7#aj74 #ac ,chamberlain 7#ab7 p4 #aa4 #ad ,saxton 7#ajd74 #ae ,for an explanation of the occurrence of a single cotyledon in ,ceratozamia1 see ,dorety 7#jh74 #af ,worsdell 7#jj72 7#ja72 ,chamberlain 7#aa74 #ag 1 porous1 loose in texture2 1 compact4 #ah ,sifton 7#ae74 #ai ,worsdell 7#jj72 7#jf74 ,see postea1 ,chap4 xxx4 #bj ,worsdell 7#ih74 #ba ,for figures1 see ,mettenius 7#fj7 ,b42 de ,bary 7#hd7 ,a42 le ,goc 7#ad72 ,marsh 7#ad74 #bb ,wieland 7#jf7 pp4 #fb1 #fc4 #bc ,matte 7#jd7 ,pl4 vii4 fig4 #aaa4 #bd ,scott 7#ig72 ,matte 7#jd7 p4 #afd4 #be ,the species ,cycas taiwanensis was founded by ,mr ,carruthers 7#ic7 on material from ,formosa1 and ,c4 revoluta has also been recorded from ,formosa ,thiselton-,dyer 7#jb7 p4 #eei1 but according to ,mr ,elwes it is very doubtful whether any native ,cycad occurs on the island4 #bf ,engler 7#ie7 p4 #ib2 ,stapf 7#ad74 #bg ,gard4 ,chron4 ,june #aa1 #aijd1 p4 #cgj4 #bh ,bot4 ,mag4 #aiji1 ,tab4 #hbcb4 #bi ,pearson 7#jf74 #cj ,chamberlain 7#ab74 #ca ,chamberlain 7#jf74 #cb ,webber 7#ja74 #cc ,chamberlain 7#ji74 #cd ,hooker1 ,j4 ,d4 7#ia7 ,a4 p4 #ih 7footnote74 #ce ,pearson 7#jf74 #cf ,prof4 de ,vries kindly informed me in a letter that this estimate is not to be regarded as anything more than a rough guess4 #cg ,stopes 7#aj74 #ch ,caldwell 7#jg74 #ci ,bower 7#hd74 #dj ,rosen 7#aa74 #da ,seward 7#ie7 ,a4 pp4 #ae et seq4 #db ,braun1 ,a4 7#ge74 #dc ,thiselton-,dyer 7#fe7 ,b42 ,bot4 ,mag4 #aiji1 ,tab4 #hbdb4 #dd ,thiselton-,dyer 7#jb7 p4 #efj4 #de ,gard4 ,chron4 #aijd1 ,june #aa1 p4 #cgj4 #df ,seward 7#ig74 #dg ,braun1 ,a4 7#ge7 p4 #cgf4 #dh ,bot4 ,mag4 #ahah1 ,tab4 #aifi4 #di ,matte 7#jd7 p4 #cd4 #ej ,seward 7#ie7 ,a4 p4 #e2 ,robertson 7#jb7 fig4 #d4 #ea ,vol4 ii4 fig4 #bhg1 p4 #chi4 #eb ,chamberlain 7#ji74 #ec ,braun1 ,a4 7#ge72 ,bornemann 7#ef7 ,a4 ,pl4 x4 #ed ,caldwell 7#jg72 ,caldwell and ,baker 7#jg74 #ee ,bot4 ,mag4 #ahei1 ,tab4 #eaba4 #ef ,vol4 ii4 p4 #dhe4 #eg ,lignier 7#id74 #eh ,chamberlain 7#ab74 #ei ,for information on the anatomy of reproductive shoots1 see ,thibout 7#if72 ,scott 7#ig72 ,worsdell 7#ih72 ,matte 7#jd74 #fj ,thiselton-,dyer 7#ja72 ,bot4 ,mag4 #aiae1 ,tab4 #heib1 #heic4 ,for instances of monstrous cones1 see ,miquel 7#fi71 ,wieland 7#jb74 #fa ,chamberlain 7#ji74 #fb ,dorrien-,smith 7#aa7 p4 #bhg4 #fc ,stopes 7#jd7 p4 #dfg4 #fd ,stopes 7#jd7 p4 #dch1 fig4 #a2 ,warming 7#gg7 ,pl4 iii4 #fe ,chamberlain 7#jf74 #ff ,kershaw 7#ab74 #fg ,stopes 7#jd74 #fh ,oliver 7#ac74 #fi ,thoday 7,sykes7 7#aa72 ,sykes 7#aj72 ,thoday 7,sykes7 and ,berridge 7#ab74 #gj ,salisbury 7#ad7 p4 #gb4 #ga ,kraus 7#if74 #gb ,pearson 7#jf74 #gc ,rattray 7#ac74 #gd ,worsdell 7#if72 7#ja74 #ge ,see ante1 p4 #e4 #gf ,chamberlain 7#aa72 ,wieland 7#jf74 #gg ,pavolini 7#ji72 ,marsh 7#ad74 #gh ,matte 7#jh74 #gi ,dorety 7#jh72 7#ji74 #hj ,worsdell 7#if74 #ha ,matte 7#jd7 especially pp4 #ahe-bjb4 ,see also ,worsdell 7#jj72 7#jf7 etc4 #hb ,matte 7#jd7 p4 #baj4 #hc ,worsdell 7#ih74 #hd ,caldwell 7#jg74 #he ,carano 7#jd72 le ,goc 7#ad72 ,marsh 7#ad74 #hf ,le ,goc 7#ad72 ,marsh 7#ad74 #hg ,seward 7#jf74 #hh ,robertson 7#jb74 #hi ,seward 7#ab74 #ij ,worsdell 7#ih74 #ia ,lignier 7#ib74 #ib ,nestler 7#ie72 ,porsch 7#je72 ,thomas and ,bancroft 7#ac72 ,dunek 7#ac74 #ic ,binney 7#ff74 #id ,unger 7#ej7 ,a4 p4 #cgh4 #ie ,williamson 7#fi74 #if ,williamson 7#gc7 ,a4 #ig ,gourlie 7#dd74 #ih ,see page #ahf4 #ii ,solms-,laubach 7#ia7 ,a4 pp4 #h1 #bag1 #bah4 #ajj ,solms-,laubach 7#ia7 ,a4 pp4 #h1 #bag1 #bah4 #aja ,vol4 ii4 p4 #bbj4 #ajb ,nathorst 7#ad7 ,pl4 vii4 fig4 #a4 #ajc ,nathorst 7#jd7 ,b4 p4 #aa4 #ajd ,potoni 7#ii7 ,b4 p4 #aga4 #aje ,arber1 ,e4 ,a4 ,n4 7#jb74 #ajf ,williamson and ,scott 7#ie74 #ajg ,williamson and ,scott 7#ie7 p4 #gbj4 #ajh ,williamson 7#ij7 ,pl4 xii4 fig4 #f4 #aji ,williamson 7#ij7 ,pl4 xiii4 fig4 #c1 b4 #aaj ,williamson and ,scott 7#ie7 ,pl4 xxiii4 fig4 #h4 #aaa ,ibid4 p4 #gbb4 #aab ,worsdell 7#jf7 pp4 #adj et seq4 #aac ,lomax 7#jb74 #aad ,brenchley 7#ac74 #aae ,for a description of the method1 see ,salisbury 7#ac74 #aaf ,williamson 7#gc7 ,a4 p4 #djc4 #aag ,williamson 7#ij74 #aah ,vol4 ii4 p4 #bii1 fig4 #bcb4 #aai ,bower 7#ab7 ,pls4 xxx4 xxxiii4 #abj ,hhlke 7#jb74 #aba ,williamson 7#gd7 ,pl4 li4 fig4 #a4 #abb ,scott 7#ji7 ,b4 fig4 #aci1 p4 #cge4 #abc ,brongniart 7#bh7 ,a4 p4 #aii1 ,pl4 lii4 ,for synonymy1 see ,kidston 7#aa7 p4 #db4 #abd ,zeiller 7#hh7 ,a4 p4 #hb1 ,pl4 vi4 #abe ,see also ,kidston 7#jf7 ,b1 fig4 #e1 p4 #dag2 ,renier 7#aj71 ,pls4 #fj1 #gj4 #abf ,kidston 7#jf7 ,b4 #abg ,stur 7#gg7 p4 #beg1 ,pls4 xxv4 xxvi4 #abh ,oliver 7#je7 fig4 #f4 #abi ,gothan 7#ac7 p4 #dj4 #acj ,johnson 7#aa74 #aca ,kidston 7#je74 #acb ,kidston 7#jf7 ,b4 #acc ,zeiller 7#hc7 ,b4 #acd ,gothan 7#ac7 p4 #di4 #ace ,chodat 7#jh7 ,b4 #acf ,scott 7#jh7 ,b4 p4 #bib4 #acg ,weiss1 ,f4 ,e4 7#ab74 #ach ,vol4 ii4 p4 #ecb4 #aci ,scott 7#ji7 ,b4 p4 #djj4 #adj ,kidston 7#jf7 ,b4 #ada ,benson 7#jd7 ,b4 #adb ,in his account of the ovule of ,stangeria ,lang 7#jj7 discusses the possibility of homologising the ovule with a sorus consisting of one sporangium4 #adc ,williamson 7#gg7 ,b4 p4 #bcd4 #add ,oliver and ,scott 7#jc73 7#jd74 #ade ,hrich 7#jf7 p4 #dh4 #adf ,kidston 7#je7 ,b4 #adg ,grand',eury 7#je7 ,b4 #adh ,oliver and ,scott 7#jd7 ,pl4 x4 fig4 #bh2 ,mc,lean 7#ab74 #adi ,williamson 7#gf74 #aej ,oliver 7#jc7 p4 #dfb4 #aea ,benson 7#jh74 #aeb ,mc,lean 7#ab74 #aec ,for figure1 see ,lotsy 7#ji7 p4 #gad4 #aed ,scott 7#aa7 p4 #aje4 #aee ,chodat 7#jh7 ,b4 #aef ,scott 7#jc74 #aeg ,scott 7#ji7 ,b4 p4 #bbj4 ,see also ,oliver 7#je72 ,oliver and ,scott 7#jd7 p4 #bca4 #aeh ,gibbs 7#ab7 p4 #df4 #aei ,oliver 7#jf74 #afj ,stopes7#je72 ,prankerd 7#ab74 #afa ,sykes 7#aj7 p4 #bai2 ,thoday 7,sykes1 ,m4 ,g47 7#aa7 p4 #aabd4 #afb ,shaw 7#jh74 #afc ,benson and ,welsford 7#ji7 p4 #fcc4 #afd ,kershaw 7#ji7 p4 #cei4 #afe ,benson 7#jh74 #aff ,zopf 7#ib7 ,pls4 i4 ii4 #afg ,burlingame 7#ae74 #afh ,williamson 7#gg7 ,b4 #afi ,williamson 7#gf7 p4 #afj4 #agj ,butterworth 7#ig74 #aga ,oliver 7#ji7 p4 #gd4 #agb ,prankerd 7#ab74 #agc ,vol4 ii4 p4 #cfd1 fig4 #bgj4 #agd ,berridge 7#aa74 #age ,lignier 7#ac74 #agf ,nathorst 7#ad7 p4 #bi4 #agg ,arber 7#je74 #agh ,oliver 7#ji74 #agi ,arber 7#ad7 p4 #ajb4 #ahj ,vol4 ii4 pp4 #bid1 #bie4 #aha ,vol4 ii4 p4 #ebi1 fig4 #ceb4 #ahb ,carpentier 7#aa7 p4 #c4 #ahc ,see page #ff4 #ahd ,kidston 7#ad7 p4 #afj1 ,pl4 vii4 figs4 #a1 #b4 #ahe ,ibid4 p4 #afa1 ,pl4 xvi4 figs4 #i1 #aj4 #ahf ,grand',eury 7#je7 ,b4 #ahg ,carpentier 7#aa74 #ahh ,arber1 ,e4 ,a4 ,n4 7#jh74 #ahi ,nathorst 7#jh7 p4 #aj1 ,pl4 ii4 figs4 #ai-ba4 #aij ,stopes 7#ad7 p4 #gd1 ,pls4 xvii4 fig4 #de1 xxv4 fig4 #fi1 text-fig4 #ae4 #aia ,see page #abd4 #aib ,nathorst 7#ad7 p4 #bc1 ,pl4 xv4 fig4 #dc4 #aic ,carpentier 7#ac7 p4 #cia4 #aid ,williamson 7#gf7 ,b4 #aie ,williamson 7#hg7 p4 #big4 #aif ,felix 7#hf7 ,a4 p4 #ea4 #aig ,williamson and ,scott 7#id74 #aih ,hick 7#ie7 p4 #aad4 #aii ,stopes and ,watson 7#jh7 ,pl4 xvii4 fig4 #a4 #bjj ,weiss1 ,f4 ,e4 7#ac74 #bja ,williamson and ,scott 7#ie7 p4 #gci4 #bjb ,white 7#ii7 ,b4 p4 #dj4 #bjc ,felix 7#hf7 ,a4 #bjd ,zalessky 7#aj74 #bje ,kubart 7#ad72 7#aa74 #bjf ,corda 7#de7 ,a4 ,pl4 xvi4 #bjg ,kubart 7#jh7 fig4 #c4 #bjh ,vol4 ii4 p4 #caj1 fig4 #bcg1 ,c2 p4 #caa1 fig4 #bch4 #bji ,williamson 7#gc7 ,a4 p4 #djc4 #baj ,benson 7#ad74 #baa ,williamson 7#gb74 #bab ,williamson 7#gc7 ,a4 #bac ,williamson 7#ij74 #bad ,williamson and ,scott 7#ie74 #bae ,scott 7#ae74 #baf ,scott 7#ae74 #bag ,jeffrey 7#je7 ,pl4 iii4 fig4 #ba4 #bah ,kidston 7#ia7 ,b4 p4 #di4 #bai ,williamson and ,scott 7#ie7 p4 #gec4 #bbj ,williamson and ,scott 7#ie7 ,pl4 xxvii4 fig4 #bh4 #bba ,stur 7#gg7 p4 #bcf1 ,pls4 xiii4 xiv4 #bbb ,benson 7#ad74 #bbc ,oliver 7#ji7 p4 #aaa4 #bbd ,grand',eury 7#je74 #bbe ,carpentier 7#aa7 ,pl4 xii4 fig4 #a4 #bbf ,for a fuller description1 see ,williamson and ,scott 7#ie74 #bbg ,scott 7#ji7 ,b4 p4 #daj2 7#ae74 #bbh ,scott 7#ae74 #bbi ,renault 7#gi7 ,b4 p4 #bgf1 ,pl4 xiv4 figs4 #d-h2 7#if7 ,a4 p4 #bea1 ,pl4 lxv4 figs4 #a1 #b4 #bcj ,renault 7#if7 ,a4 pp4 #bec1 #bee4 #bca ,ibid4 p4 #beb1 ,pl4 lxv4 figs4 #c1 #f4 #bcb ,kubart 7#ad74 #bcc ,dr4 ,scott who has seen sections of this species tells me that it is a striking intermediate form4 #bcd ,johnson 7#ab74 #bce ,scott 7#ae74 #bcf ,goeppert and ,stenzel 7#ha74 #bcg ,lotsy 7#ji7 p4 #gbc4 #bch ,zeiller 7#je7 ,b4 p4 #gbe4 #bci ,schenck 7#ic7 ,b4 ,pls4 ,i-,v1 etc4 #bdj ,white1 ,d4 7#je7 ,b4 p4 #chi4 #bda ,solms-,laubach 7#ig7 ,pl4 vi4 fig4 #c4 #bdb ,penhallow 7#ig74 #bdc ,cotta 7#cb7 ,b4 p4 #ei4 #bdd ,brongniart 7#di7 ,a4 p4 #eg4 #bde ,scott 7#ii74 #bdf ,arber1 ,e4 ,a4 ,n4 7#jc74 #bdg ,renault 7#gf7 ,b4 #bdh ,arber1 ,e4 ,a4 ,n4 7#jc74 #bdi ,kidston 7#je7 ,b4 #bej ,scott 7#ji7 ,b4 p4 #dda 7footnote74 #bea ,scott 7#ad74 #beb ,de ,fraine 7#ad74 #bec ,de ,fraine 7#ad7 p4 #bei4 ,see also ,kisch 7#ac74 #bed ,cotta 7#cb7 ,b4 p4 #ff1 ,pl4 xiii4 ,the well-preserved specimen figured by ,cotta in his ,pl4 xiii4 fig4 #b is in the ,dresden ,museum4 #bee ,goeppert 7#fe7 ,a4 p4 #bji1 ,pls4 xl4-xliii4 #bef ,goeppert and ,stenzel 7#ha74 #beg ,weber and ,sterzel 7#if7 ,b4 #beh ,schenk 7#hi74 #bei ,weber and ,sterzel 7#if7 ,b4 p4 #ea2 ,schenk 7#hi74 #bfj ,no4 ,v4 #hjic4 #bfa ,schenk 7#hb74 ,see also ,zeiller 7#ij7 ,b4 p4 #bhf4 #bfb ,no4 #acgfg1 probably identical with ,m4 stellata var4 lignosa ,weber and ,sterzel4 #bfc ,mougeot 7#eb7 ,a4 p4 #cf1 ,pl4 iii4 figs4 #h-aj4 #bfd ,weber and ,sterzel 7#if7 ,b4 p4 #ajh4 #bfe ,ibid4 p4 #ef4 #bff ,weber and ,sterzel 7#if7 ,b4 p4 #fc4 #bfg ,ibid4 p4 #ff4 #bfh ,renault 7#if7 ,a4 p4 #big2 7#ic7 ,a4 ,pl4 lxxi4 figs4 #a-f4 #bfi ,brongniart 7#di7 ,a4 p4 #gg4 #bgj ,cotta 7#cb7 ,b4 p4 #fc1 ,pl4 xii4 figs4 #f1 #g4 #bga ,schenk 7#hi7 p4 #cci4 #bgb ,weber and ,sterzel 7#if7 ,b4 p4 #eda1 ,pls4 ii4 iii4 #bgc ,goeppert and ,stenzel 7#ha7 p4 #abc1 ,pl4 xvi4 figs4 #ac-ae2 ,solms-,laubach 7#ig72 ,weber and ,sterzel 7#if7 ,b4 p4 #gi1 ,pls4 iv4 v4 ix4 #bgd ,goeppert and ,stenzel 7#ha7 ,pl4 iii4 fig4 #ae4 #bge ,solms-,laubach 7#ig7 p4 #agi4 #bgf ,scott 7#ii7 p4 #ij4 #bgg ,weber and ,sterzel 7#if7 ,b4 p4 #ie1 ,pl4 ix4 #bgh ,solms-,laubach 7#ig74 #bgi ,renault 7#gf7 ,b4 p4 #g4 #bhj ,grand',eury 7#gg7 ,a4 p4 #abb2 7#ij7 ,a4 p4 #bhg4 #bha ,seward 7#ic74 #bhb ,penhallow 7#ig74 #bhc ,williamson 7#gf7 ,b4 p4 #h4 #bhd ,zeiller 7#ij7 ,b4 #bhe ,weber and ,sterzel 7#if7 ,b4 p4 #ajb1 fig4 #bf4 #bhf ,seward 7#ic74 #bhg ,renault 7#gf7 ,b4 #bhh ,penhallow 7#ig74 #bhi ,weber and ,sterzel 7#if7 ,b4 p4 #aci4 #bij ,page #adb4 #bia ,holden1 ,h4 ,s4 7#aj74 #bib ,vol4 ii4 p4 #efh1 fig4 #cga4 #bic ,kidston 7#hg7 ,b4 #bid ,bertrand1 ,p4 7#ac7 p4 #aag4 #bie ,carpentier 7#aa7 p4 #aj4 #bif ,lesquereux 7#hj7 ,a4 p4 #cbh1 ,pl4 xlviii4 #big ,bertrand1 ,p4 7#ac7 p4 #abj4 #bih ,zeiller 7#ii7 ,b4 p4 #eb1 ,pl4 iv4 fig4 #ai4 #bii ,carpentier 7#aa7 p4 #ab1 ,pls xvi4 xvii4 #cjj ,carpentier 7#ac7 p4 #chg1 ,pl4 x4 figs4 #a-f4 #cja ,bertrand1 ,p4 7#ac7 p4 #abe4 #cjb ,kidston 7#ad7 p4 #ajh4 #cjc ,ibid4 p4 #aab1 ,pl4 viii4 figs4 #a-g4 #cjd ,carpentier 7#aa7 p4 #ac1 ,pl4 xvi4 fig4 #a4 #cje ,see page #abg4 #cjf ,renault and ,zeiller 7#hh7 ,a4 p4 #bgc1 ,pl4 xxxi4 figs4 #b1 #d4 #cjg ,zeiller 7#ij7 ,b4 ,pl4 xi4 fig4 #i2 7#jj7 ,b4 p4 #ajh1 fig4 #hc4 ,see ,vol4 ii4 p4 #egb4 #cjh ,bertrand1 ,p4 7#ac7 p4 #acb1 ,pl4 vi4 fig4 #g4 #cji ,carpentier 7#ac7 p4 #cge1 ,pl4 viii4 fig4 #a4 #caj ,bertrand1 ,p4 7#ac7 p4 #ace1 pl4 vi4 figs4 #b-d4 #caa ,kidston 7#jd72 7#jd72 7#ad7 p4 #ajg1 fig4 #e4 #cab ,renault and ,zeiller 7#hh7 ,a4 ,pl4 lxxii4 fig4 #ai4 #cac ,grand',eury 7#ij7 ,a4 ,pl4 vi4 fig4 #f4 #cad ,kidston and ,jongmans 7#aa74 #cae ,grand',eury 7#jd72 7#jd74 #caf ,cf4 also ,rhabdocarpus conicus and other forms figured by ,renault 7#ic7 ,a4 ,pl4 lxxxvi4 #cag ,brongniart 7#gd7 ,pl4 xxi42 7#ha7 ,pls4 ix4-xi4 #cah ,see ,chapter xxxv4 #cai ,see ,chapter xxxv4 #cbj ,p4 ,bertrand 7#ac7 p4 #abi1 ,pl4 vii4 figs4 #a1 #b1 #g4 #cba ,see ,chapter xxxv4 #cbb ,see page #aci4 #cbc ,arber 7#ad7 pp4 #ic1 #ajc1 ,pl4 viii4 fig4 #dg4 #cbd ,p4 ,bertrand 7#ac7 p4 #aba4 #cbe ,grand',eury 7#jd7 p4 #ghe 7footnote74 #cbf ,chodat 7#jh7 ,b4 p4 #cc1 fig4 #ae4 #cbg ,lotsy 7#ji7 p4 #gb4 #cbh ,grand',eury 7#jd72 7#jd7 ,b4 #cbi ,brongniart 7#bh7 ,a4 p4 #acg4 #ccj ,williamson 7#gg7 ,b42 ,scott and ,maslen 7#jg7 p4 #ij 7footnote7 also refer to ,trigonocarpon as having been used by ,brongniart in #ahdi4 #cca ,brongniart 7#di7 ,a4 p4 #ia4 #ccb ,lindley and ,hutton 7#ce7 ,a4 p4 #agb4 #ccc ,hooker and ,binney 7#ee74 #ccd ,lindley and ,hutton 7#cc7 ,a4 ,pl4 #hg4 #cce ,wild 7#jj74 #ccf ,scott and ,maslen 7#jg7 p4 #if4 #ccg ,scott and ,maslen 7#jg74 #cch ,arber1 ,a 7#ad74 #cci ,oliver 7#jd7 p4 #ig4 #cdj ,salisbury 7#ad7 p4 #fe4 #cda ,arber1 ,e4 ,a4 ,n4 7#ad7 p4 #ie1 ,pl4 vi4 fig4 #a4 #cdb ,lindley and ,hutton 7#cg7 ,a4 ,pl4 #bba2 ,arber loc4 cit4 p4 #ie1 ,pl4 vi4 fig4 #h4 #cdc ,fiedler 7#eg7 ,pl4 xxvii4 fig4 #ci4 #cdd ,lesquereux 7#hj7 ,a4 ,pl4 #he2 7#hd7 ,a4 ,pl4 iii4 #cde ,salisbury 7#ad74 #cdf ,see page #aae4 #cdg ,renault 7#if7 ,a4 p4 #cii2 7#ic7 ,a4 ,pl4 lxxxv4 fig4 #i2 ,salisbury 7#ad7 p4 #ff4 #cdh ,sellards 7#jc7 p4 #ij2 7#jg74 #cdi ,lesquereux 7#hj7 ,a4 p4 #ic2 7#hd7 ,a4 p4 #gcc1 ,pl4 xciv4 figs4 #a1 #b4 #cej ,stopes 7#ad7 p4 #gd4 ,see page #ff4 #cea ,nathorst 7#ad7 p4 #bc4 ,see page #fg4 #ceb ,geinitz 7#fc7 p4 #ebe1 ,pl4 vi4 #cec ,goeppert 7#fe7 p4 #afa1 ,pls4 ,,xxiii-,,iv4 ,the specimens figured by ,goeppert1 which ,i saw some years ago in the ,breslau ,museum1 do not show the finer characters very clearly4 #ced ,goeppert 7#fe7 p4 #afd1 ,pls4 ,,xxiv-,v4 #cee ,schimper 7#gb7 ,a4 p4 #ceh4 #cef ,kidston 7#hd7 ,pl4 v4 fig4 #b4 #ceg ,renault 7#if7 ,a4 p4 #cgi1 fig4 #gc4 #ceh ,zeiller in ,douvill and ,zeiller 7#jh74 #cei ,see page #abd4 #cfj ,newberry 7#ed74 #cfa ,lesquereux 7#hj7 ,a4 p4 #ebc1 ,pl4 iv2 7#hd74 ,for other references see ,potoni 7#jd74 #cfb ,white1 ,d4 7#ja74 #cfc ,thomas1 ,h4 ,h4 7#ab72 ,kidston 7#ad7 p4 #aff4 #cfd ,renault 7#ic7 ,a4 ,pl4 lxxii2 7#if7 ,a4 p4 #bfh4 ,see page #acg4 #cfe ,page #aaa4 #cff ,white 7#ja7 p4 #ajh4 #cfg ,ibid4 p4 #ajd1 ,pl4 vii4 figs4 #c1 #c;a4 #cfh ,matthew 7#aj74 #cfi ,stopes 7#ad7 p4 #gh4 #cgj ,kidston 7#ad7 p4 #aff1 ,pl4 xv4 figs4 #a-aj4 #cga ,saporta 7#gh74 #cgb ,eichwald 7#ee7 ,pl4 xviii4 fig4 #ah2 7#fj7 p4 #beb4 #cgc ,goeppert 7#fe7 p4 #aeg1 ,pl4 xxi4 fig4 #d4 #cgd ,saporta 7#gh74 #cge ,saporta and ,marion 7#he7 pp4 #af1 #fh4 #cgf ,grand',eury 7#gg7 ,a4 p4 #aib4 #cgg ,zeiller 7#jj7 ,b4 p4 #bag4 #cgh ,kutorga 7#db74 #cgi ,unger 7#ej7 ,a4 p4 #ccd4 #chj ,renault 7#if7 ,a4 p4 #bfb4 #cha ,no4 ,v4 #haad4 #chb ,a specimen from ,orenburg in the ,dresden ,museum shows the same surface-features as the ,british ,museum specimen and agrees with the originals of ,goeppert's figures which are in the ,breslau ,university ,museum4 #chc ,renault 7#if7 ,a4 p4 #bfe1 fig4 #dc4 #chd ,renault 7#if7 ,a4 p4 #bfb1 ,pl4 xxii4 fig4 #a4 #che ,grand',eury 7#gg7 ,a4 p4 #aif1 ,pl4 xvi2 7#ij7 ,a4 ,pl4 viii4 fig4 #a2 ,zeiller 7#jf7 ,b4 p4 #aib4 #chf ,renault and ,zeiller 7#ij7 ,a4 p4 #eef1 ,pl4 lvii4 #chg ,grand',eury 7#jd74 #chh ,roehl 7#fi7 ,b4 ,pl4 xvii4 #chi ,saporta and ,marion 7#he7 fig4 #bi4 #cij ,renault 7#if7 ,a1 p4 #bfg1 ,pl4 lxxii4 #cia ,solms-,laubach 7#ia7 ,a4 p4 #abf4 #cib ,see ,chapter xxxv4 #cic ,zeiller 7#jf7 ,b4 p4 #bbg4 #cid ,saporta and ,marion 7#he7 fig4 #cg1 p4 #gf4 #cie ,schmalhausen 7#hg7 ,pl4 v4 figs4 #g-i3 this specimen1 figured as ,dolerophyllum ,goepperti1 is very similar to ,cordaites circularis ,grand',eury 7#ij7 ,a4 ,pl4 vi4 fig4 #ae4 #cif ,zeiller 7#jb7 ,b4 p4 #cd1 ,pl4 iv4 figs4 #i1 #aj4 #cig ,bertrand1 ,p4 7#ac7 p4 #aca1 ,pl4 vii4 fig4 #f4 #cih ,zeiller1 loc4 cit4 p4 #cg4 #cii ,feistmantel 7#gi7 ,b4 p4 #cj2 7#ha7 ,a4 p4 #ei1 ,pl4 xxx4 fig4 #ad2 7#hb7 ,b4 p4 #dc1 ,pl4 xv4 figs4 #e-ab4 ,dr ,arber 7#je7 ,b4 p4 #bje has substituted for ,carpolithes the more appropriate designation ,cardiocarpus4 #djj ,renault 7#if7 ,a4 p4 #cbi2 7#ic7 ,a4 ,pl4 lxxiii4 #dja ,schimper and ,mougeot 7#dd7 ,a4 p4 #ca4 ,seward 7#jh7 ,b4 p4 #aja4 #djb ,brongniart 7#di7 ,a4 p4 #fj4 #djc ,renault 7#if7 ,a4 p4 #bii2 7#ic7 ,a4 ,pls4 #ff1 #fg4 #djd ,grand',eury 7#jh7 ,b4 p4 #abdb4 #dje ,goeppert and ,stenzel 7#ha7 p4 #abe2 ,weber and ,sterzel 7#if7 ,b4 p4 #gi4 ,solms-,laubach 7#ig7 p4 #aif draws attention to the resemblances between the leaf-scars of ,colpoxylon and ,medullosa4 #djf ,klein 7#ha7 ,pls4 xxii4-xxiv4 #djg ,bancroft 7#ac74 #djh ,page #bje4 #dji ,scott 7#jf74 #daj de ,fraine 7#ab74 #daa ,scott 7#jf7 p4 #ec4 #dab de ,fraine 7#ab74 #dac ,reference should be made to the helpful drawings of models of the vascular system in ,miss de ,fraine's paper4 #dad ,for additional figures of the principal types of ,medullosa1 see ,miss ,bancroft's paper 7#ad74 #dae ,lotsy 7#ji7 p4 #gai4 #daf ,scott 7#ad7 p4 #iih4 #dag ,scott 7#ii7 p4 #hi4 #dah ,worsdell 7#if72 7#ih72 7#jj72 7#jf7 etc4 #dai ,matte 7#jd72 7#jh74 ,see also ,bancroft 7#ad72 ,dorety 7#ji74 #dbj ,scott 7#ig74 #dba ,worsdell 7#jf74 #dbb ,shaw 7#ji74 #dbc de ,fraine 7#ab7 p4 #ajfj4 #dbd ,sykes1 ,m4 ,g4 7#aj72 7#aj74 #dbe ,matte 7#jd7 ,pls4 xv4 xvi4 #dbf de ,fraine 7#ab74 #dbg ,scott 7#jf7 p4 #fd4 #dbh ,chodat 7#jh7 ,b4 p4 #ch4 #dbi ,worsdell 7#jf7 pp4 #adj et seq4 #dcj ,scott 7#ji7 ,b4 p4 #dfd4 #dca ,for a general summary of #8,pteridosperm anatomy and its relation to that of the ,cycads' see ,bancroft 7#ad74 #dcb ,see p4 #f4 #dcc ,dorety 7#ji7 p4 #add4 #dcd ,goeppert and ,stenzel 7#ha7 p4 #abf1 ,pl4 xvii4 #dce ,schenk 7#hi7 p4 #ebe1 ,pl4 i4 figs4 #a-af4 #dcf ,solms-,laubach 7#if7 ,b4 p4 #fb2 7#ig7 p4 #aig2 7#aj7 p4 #edb1 ,pl4 iii4 fig4 #i4 #dcg ,p4 ,bertrand 7#jh72 7#aa7 p4 #dg 7footnote74 #dch ,in a recent note on ,steloxylon to which ,dr ,scott has drawn my attention ,bertrand records the genus from ,saalfeld 7,upper ,devonian7 and expresses the opinion that ,steloxylon may be a condition of ,cladoxylon and not a distinct type--,p4 ,bertrand 7#ad7 p4 #ddh4 #dci ,vol4 ii4 p4 #egf4 #ddj ,schlotheim 7#jd7 ,a4 ,pl4 x1 fig4 #ai4 #dda ,for synonymy1 see ,kidston 7#hf7 ,a4 p4 #abe and ,potoni 7#ic7 ,a4 p4 #ha4 #ddb ,sterzel 7#hc72 7#hf7 ,b42 ,zeiller 7#jf7 ,b4 p4 #fj4 #ddc ,stur 7#he7 ,b4 p4 #bic4 #ddd ,grand',eury 7#je74 #dde ,see also ,zeiller 7#je7 ,b4 p4 #gbe4 #ddf ,grand',eury 7#gg7 ,a4 ,pl4 xxxiii4 fig4 #g4 #ddg ,vol4 ii4 p4 #dai1 fig4 #big4 #ddh ,zeiller 7#jf7 ,b4 p4 #fc4 #ddi ,for a more complete synonymy1 see ,kidston 7#jc7 ,b4 p4 #ggj4 #dej ,brongniart 7#bh7 ,a4 ,pls4 xlvi41 xlvii42 ,lebour 7#gg7 ,pls4 xxxiii4-iv4 #dea ,kidston 7#ad7 p4 #aef2 ,duns 7#gb74 #deb ,howse 7#hh7 p4 #de4 #dec ,arber1 ,e4 ,a4 ,n4 7#ad7 p4 #ig2 7#ji7 p4 #bi1 ,pl4 i4 fig4 #e4 #ded ,kidston 7#hc7 ,b4 p4 #edj1 ,pl4 xxxii4 fig4 #c4 #dee ,white refers some fronds from the ,missouri ,coal ,measures to ,eremopteris1 but their generic identity with the type-species is open to doubt4 ,white 7#ii7 ,b4 p4 #af4 #def ,white 7#jd7 ,b4 #deg ,vol4 ii4 p4 #cgf4 #deh ,goeppert 7#cf7 ,a4 p4 #baf4 #dei ,see page #fd4 #dfj ,nathorst 7#ad7 p4 #cj1 ,pl4 xv4 figs4 #ah1 #fj-fh4 #dfa ,schmalhausen 7#hc7 ,pl4 iv4 figs4 #ac-ae4 #dfb ,heer 7#gg7 ,a4 ,pl4 v4 pp4 #bc-be4 #dfc ,nathorst 7#ad7 p4 #cj1 ,pl4 xv4 fig4 #ei4 #dfd ,kidston 7#hf7 p4 #gj1 ,pl4 iii4 fig4 #f4 #dfe ,arber1 ,e4 ,a4 ,n4 7#ad7 p4 #if1 ,pl4 vi4 fig4 #ab4 #dff ,seward 7#ii7 ,b4 #dfg ,for additional figures1 see ,seward 7#ii7 ,b4 #dfh ,vol4 ii4 p4 #cbf4 #dfi ,scott 7#ji7 ,b4 p4 #dgf4 #dgj ,gordon 7#ab74 ,the rich development of secretory tissue suggested the name ,rhetinangium 71 resinous gum73 the same prefix had previously been adopted by ,renault in his genus ,retinodendron ,renault 7#if7 ,a4 p4 #cfe4 #dga ,scott 7#ae74 #dgb ,page #ij4 #dgc ,kubart 7#ad74 #dgd ,kidston and ,gwynne-,vaughan 7#ab74 #dge ,similar to the ,dictyoxylon type except in the independent and not anastomosing course of the stereome strands4 #dgf ,kidston and ,gwynne-,vaughan 7#ab7 p4 #bfi4 #dgg ,renault 7#if7 ,a4 p4 #cjg4 #dgh ,renault 7#if7 ,a4 p4 #cjh1 figs4 #ee1 #ef4 #dgi ,seward 7#ig74 #dhj ,scott 7#jj7 ,b4 p4 #cfd4 #dha ,a second band is sometimes present4 ,scott 7#jj7 ,b4 p4 #dhd4 #dhb 1 a fold4 #dhc ,renault 7#hi72 7#if7 ,a2 7#ic7 ,a4 ,pl4 lxix4 #dhd ,scott 7#ji7 ,b4 p4 #dib4 #dhe ,klein 7#ha74 #dhf ,richter and ,unger 7#ef7 ,b4 #dhg ,unger 7#ed7 p4 #eii4 #dhh ,solms-,laubach 7#if7 ,b4 #dhi ,zalessky 7#aa74 #dij ,scott and ,jeffrey 7#ad74 #dia 1 a veil or covering4 #dib ,white 7#je7 ,b4 p4 #chd4 #dic ,richter and ,unger 7#ef7 ,b4 p4 #agd1 ,pl4 x4 figs4 #a-c2 ,solms-,laubach 7#if7 ,b4 p4 #gc2 ,scott 7#ab7 p4 #ajbg4 #did ,scott and ,jeffrey 7#ad7 p4 #cbf4 #die ,ibid4 p4 #cag1 ,pls4 #bg1 #bh1 #cj1 #ca4 #dif ,scott 7#jb74 #dig ,scott and ,jeffrey 7#ad7 p4 #cbh1 refer to a specimen over #f cm4 in diameter3 these authors give several excellent figures of ,kalymma4 #dih ,dawson and ,penhallow 7#ia74 #dii 1 to be disputed4 #ejj ,zalessky 7#aa74 #eja ,scott 7#ii74 #ejb ,scott 7#jb74 #ejc ,scott 7#jb7 p4 #ccf4 #ejd ,page #age4 #eje ,scott 7#ab7 p4 #ajbg4 #ejf ,tuzson 7#ji74 #ejg ,unger and ,richter 7#ef7 ,b4 p4 #agh4 #ejh ,scott and ,jeffrey 7#ad7 p4 #cfd4 #eji ,solms-,laubach 7#if7 ,b4 #eaj ,p4 ,bertrand 7#jh74 #eaa ,unger and ,richter 7#ef7 ,b4 p4 #agi1 ,pl4 xii4 figs4 #f1 #g2 ,solms-,laubach 7#if7 ,b4 p4 #eb1 ,pl4 ii4 figs4 #aa1 #ac7874 #eab ,unger and ,richter1 ,pl4 xii4 figs4 #c1 #d2 ,solms-,laubach 7#if7 ,b4 ,pl4 xi4 fig4 #aj4 #eac ,see footnote #c1 p4 #bje4 #ead ,solms 7#if7 ,b4 p4 #ec4 #eae ,dawson 7#ha7 ,a4 p4 #bii1 ,pl4 xii4 figs4 #a-i2 ,solms-,laubach 7#ia7 ,a4 pp4 #agc1 #ahh4 #eaf ,this type is represented in the ,geological ,survey ,collection 7,no4 #aehga74 #eag ,for figures1 see ,solms-,laubach 7#if7 ,b4 ,pl4 ii4 #eah ,no4 #aehgj4 ,unger and ,richter 7#ef7 ,b4 ,pl4 vii4 figs4 #ai-ba4 #eai ,page #dgb1 fig4 #cbd4 #ebj ,solms-,laubach 7#aj7 p4 #edj4 #eba ,bertrand1 ,p4 7#aa7 p4 #dg4 #ebb ,since this account was printed my attention has been drawn by ,dr ,scott to a note by ,bertrand in which he considerably modifies his views4 ,he finds that ,hierogramma and ,syncardia are probably different states of the petiole of ,cladoxylon and while agreeing with ,solms-,laubach's conclusions he has been able to add important new facts4 ,bertrand has now given up the opinion that ,clepsydropsis is the petiole of ,cladoxylon4 ,for further details students should consult the preliminary note which it is hoped will be followed by a fully illustrated memoir ,bertrand1 ,p4 7#ad74 #ebc ,solms-,laubach 7#aj7 p4 #ecg1 ,pl4 iii4 figs4 #g1 #aa1 #ac4 #ebd ,bancroft 7#ac74 #ebe ,after the late ,herr ,vlkel of ,neurode4 #ebf ,solms-,laubach 7#aj71 ,pl4 iii4 figs4 #a-d4 #ebg ,goeppert 7#eb7 ,pl4 xii4 #ebh ,solms-,laubach 7#ia7 ,a4 p4 #afd4 #ebi ,p4 ,bertrand 7#jh74 #ecj ,the name ,palaeopitys1 with which ,protopitys might be confused1 was used by ,mc,nab for an imperfect specimen from the ,old ,red ,sandstone of ,scotland described as ,palaeopitys ,milleri2 ,mc,nab 7#gj74 #eca ,kraus 7#ib74 #ecb ,solms-,laubach 7#ic74 #ecc ,vol4 ii4 p4 #bab1 fig4 #bjj1 ,a1 ,b4 #ecd ,see page #bjf4 #ece ,in the form of the pits on the tracheids and in the structure of the medullary rays the ,english species 7as represented in ,dr ,kidston's ,collection7 agrees very closely with ,goeppert's type4 #ecf ,gothan 7#jg7 p4 #aj4 #ecg ,renault 7#gi7 ,b4 p4 #bgb1 ,pls4 xiii1 xiv4 #ech ,bertrand and ,renault 7#hb72 ,bertrand1 ,c4 ,e4 7#hi72 ,renault 7#if7 ,a4 p4 #bgi1 7#ic7 ,a4 ,pls4 lxxiv4 lxxv2 ,scott 7#ji7 ,b4 p4 #ejj4 ,see also ,scott and ,maslen 7#aj7 ,maslen 7#aa7 p4 #dji4 #eci ,grand',eury 7#je74 #edj ,lignier 7#aa74 #eda ,renault 7#hj74 #edb ,renault 7#ic7 ,a4 ,pl4 lxxiv4 fig4 #h4 #edc ,see page #bgj4 #edd ,see ,vol4 i4 p4 #gf1 fig4 #ac4 #ede ,see ,vol4 iv4 #edf ,for restorations1 see ,grand',eury 7#gg7 ,a4 ,pl4 d2 good examples of foliage-shoots are figured by ,renault and ,zeiller 7#hh7 ,a4 ,pls4 lxvi4 lxxxi42 ,grand',eury 7#ij7 ,a4 ,pl4 lxiv42 ,kidston 7#jb7 ,b4 ,pl4 lxiv4 fig4 #b4 #edg ,renault 7#gi7 ,b4 ,pl4 xvi4 fig4 #a2 ,lignier 7#ac74 ,cf4 ,dolerophyllum1 p4 #acc4 #edh ,sternberg 7#bc7 ,a4 ,pl4 xviii4 #edi ,brongniart 7#di7 ,a4 p4 #fe4 #eej ,unger 7#ej7 ,a4 p4 #bgg4 #eea ,tuzson 7#ji7 p4 #ah4 #eeb ,grand',eury 7#gg7 ,a4 p4 #beg4 #eec ,schenk in ,schimper and ,schenk 7#ij7 ,a4 p4 #bdc4 #eed ,endlicher 7#dg7 p4 #bih4 #eee ,scott 7#ab7 p4 #ajbd4 #eef ,grand',eury 7#je74 #eeg ,benson 7#ab74 #eeh ,scott 7#ab7 p4 #ajbb4 #eei ,grand',eury 7#gg7 ,a4 p4 #bjh4 #efj ,grand',eury 7#ij7 ,a4 p4 #cba4 #efa ,renault 7#gi7 ,a4 ,pl4 xvi4 fig4 #g4 #efb ,lesquereux 7#gh7 p4 #cah4 #efc ,felix 7#hf7 ,a4 ,pl4 iii4 fig4 #a4 #efd ,renault 7#gi7 ,a4 ,pl4 xvi4 fig4 #aa bis2 ,wills1 ,l4 7#ad74 #efe ,renault 7#gi7 ,a4 ,pl4 xvi4 fig4 #e2 ,stopes 7#jc7 ,pl4 ix4 fig4 #a2 ,lignier 7#ac74 #eff ,benson 7#ab74 #efg ,lignier 7#ac74 #efh ,germar 7#dh7 ,b4 p4 #ee1 ,pl4 xxiii4 #efi ,kidston 7#ic7 ,a4 ,pl4 iv4 fig4 #af2 7#jb7 ,b4 ,pl4 lxiv4 fig4 #c4 #egj ,kidston 7#ic7 ,a4 p4 #ceb4 #ega ,lindley and ,hutton 7#cc7 ,a4 ,pl4 #ie4 #egb ,howse 7#hh7 p4 #aab1 fig4 #g4 #egc ,geinitz 7#ee7 ,a4 p4 #dj1 ,pl4 xxi4 figs4 #g-af4 #egd ,kidston 7#ic7 ,a4 p4 #cee4 #ege ,lesquereux 7#hj7 ,a4 p4 #ecg1 ,pl4 lxxviii4 #egf ,geinitz 7#fb7 p4 #adh1 ,pl4 xxxv4 #egg ,sternberg 7#bc7 ,a4 ,pl4 xviii4 #egh ,corda 7#de7 ,a4 ,pl4 xxiv4 fig4 #h4 #egi ,feistmantel 7#gb7 p4 #bic4 #ehj ,lesquereux 7#gh74 #eha ,white 7#ii7 ,b4 p4 #bfj1 ,pls4 iii4 xvi4 xlvi4 #ehb ,zeiller records the same fungus on leaves of ,cordaites 7,noeggerathiopsis7 ,hislopi from ,tonkin2 ,zeiller 7#jc7 ,b4 p4 #aea4 #ehc ,stopes 7#ad7 p4 #hb4 #ehd ,schmalhausen 7#hg7 ,pl4 vi4 #ehe ,grand',eury 7#gg7 ,a4 p4 #bah1 ,pl4 xx4 figs4 #a-d4 #ehf ,zeiller 7#jf7 ,b4 p4 #ahb1 ,pl4 xlvi42 ,grand',eury 7#ij7 ,a4 ,pl4 vii4 figs4 #a1 #b4 #ehg ,lignier 7#ac74 #ehh ,lesquereux 7#gh7 p4 #cah2 7#hj7 ,a4 ,pl4 lxxvii4 #ehi ,cambier and ,renier 7#aj72 ,renier 7#aj7 ,pl4 #aah4 #eij ,see postea4 #eia ,goeppert 7#fd7 ,a4 ,pl4 xxii4 fig4 #b4 #eib ,weiss1 ,c4 ,e4 7#gb7 p4 #aii4 #eic ,grand',eury 7#gg7 ,a4 ,pl4 xviii42 ,renault and ,zeiller 7#hh7 ,a4 ,pl4 lxvi4 #eid ,weiss1 ,c4 ,e4 7#gb7 p4 #aie4 #eie ,kidston 7#jb7 ,b4 ,pl4 lxiv4 fig4 #b4 #eif ,zeiller 7#hj7 ,a4 p4 #adf1 ,pl4 clxxv4 fig4 #a2 ,grand',eury 7#gg7 ,a4 p4 #bbe2 7#ij7 ,a4 ,pl4 vii4 fig4 #e2 ,renault and ,zeiller 7#hh7 ,a4 ,pl4 lxvii4 figs4 #a1 #b4 #eig ,lesquereux 7#hj7 ,a4 p4 #eci4 #eih ,lesquereux 7#gh7 p4 #cbb4 #eii ,schmalhausen 7#hg7 ,pl4 vi4 figs4 #d-f4 #fjj ,grand',eury 7#ij7 ,a4 p4 #cbe1 ,pl4 vi4 fig4 #ae4 #fja ,schmalhausen 7#hg7 ,pl4 v4 figs4 #g-i4 #fjb ,lesquereux 7#hj7 ,a4 p4 #ece1 ,pl4 lxxxvii4 figs4 #b-d4 #fjc ,grand',eury1 loc4 cit4 p4 #cbd1 ,pl4 iv4 fig4 #ad4 #fjd ,renault and ,zeiller 7#hh7 ,a4 p4 #fjc1 ,pl4 lxiii4 fig4 #f4 #fje ,dawson 7#ij7 p4 #c4 #fjf ,goeppert 7#de7 p4 #g1 ,pls4 xxvii4 xxviii4 #fjg ,zalessky 7#ab7 p4 #cf2 7#ab74 ,see also ,gothan 7#aa74 #fjh ,kosmovsky 7#ib74 #fji ,schmalhausen 7#gi7 ,a4 p4 #cb2 ,zeiller 7#if7 ,a4 #faj ,zeiller 7#jc7 ,b4 ,for other references see ,seward 7#ad74 #faa ,wieland 7#ac74 #fab ,mc,coy 7#gd7 ,b4 ,decade iv4 p4 #bb4 #fac ,wieland 7#ac74 #fad ,newberry 7#hh7 p4 #cej4 #fae ,feistmantel 7#gi7 p4 #bc2 7#hj74 #faf ,bunbury 7#fa7 ,b4 p4 #ccd4 #fag ,mellor and ,leslie 7#jf7 ,b4 #fah ,white 7#jh7 ,b4 p4 #edi4 #fai ,arber 7#jc7 ,b4 p4 #agh1 gives references to other authors4 #fbj ,zeiller 7#jc7 ,b4 p4 #adi1 ,pl4 xl4 #fba ,zalessky 7#ab74 #fbb ,white 7#jh7 ,b4 p4 #edi4 #fbc ,seward and ,leslie 7#jh7 ,b4 p4 #abj4 #fbd ,zalessky 7#ac7 p4 #bj1 ,pl4 ii4 figs4 #d-f4 #fbe ,the results have not yet been published 7,september1 #aiae74 #fbf ,zalessky 7#ac7 p4 #bc1 ,pls4 i4 fig4 #d2 ii4 figs4 #g1 #i2 iii4 figs4 #c1 #e-h1 #aj1 #aa4 #fbg ,schmalhausen 7#gi7 ,a4 p4 #bi4 #fbh ,zeiller 7#if7 ,a4 7#jb74 #fbi ,schmalhausen 7#hg7 ,b4 p4 #cg4 #fcj ,feistmantel 7#gi7 p4 #bf2 ,arber 7#je7 ,b4 p4 #ahf4 #fca ,feistmantel 7#hb7 p4 #db1 ,pl4 xiv42 ,white 7#jh7 ,b4 ,pl4 x2 ,schmalhausen 7#hg7 ,b4 #fcb ,schmalhausen 7#hg7 ,b4 ,pls4 v41 vii4 #fcc ,zeiller 7#jc7 ,b4 ,pl4 xl4 #fcd ,feistmantel 7#gi7 ,pl4 xiii4 fig4 #f4 #fce ,feistmantel 7#ij7 ,a4 ,pl4 xxi4 figs4 #a1 #b4 #fcf ,zeiller 7#jb7 ,b4 ,pl4 vii4 fig4 #f4 #fcg ,renault 7#gi7 ,b4 p4 #bhg4 #fch ,renault and ,zeiller 7#hh7 ,a4 ,pl4 lxxi4 #fci ,harshberger 7#ih74 #fdj ,artis 7#be7 ,a4 ,pl4 viii4 #fda ,sternberg 7#ch7 ,a4 p4 #aib4 ,for examples of ,artisia1 see also ,renault and ,zeiller 7#hh7 ,a4 p4 #eha1 ,pl4 lxv4 #fdb ,zeiller 7#jf7 ,b4 p4 #ahi4 #fdc ,dawson 7#df7 p4 #ace4 #fdd ,williamson 7#ea74 #fde ,lignier 7#ie7 ,pl4 vii4 fig4 #ac4 #fdf ,gothan 7#je7 p4 #bh4 #fdg ,see page #aii4 #fdh ,renault 7#gi7 ,b4 p4 #bhh4 #fdi ,see page #bie4 #fej ,felix 7#hf7 ,a4 p4 #ef2 ,knowlton 7#ij72 ,zeiller 7#ie7 ,b4 p4 #fbg2 ,penhallow 7#jj7 p4 #ed4 #fea ,potoni 7#jb7 p4 #bbi4 #feb ,gothan 7#je7 p4 #ac4 #fec ,gothan 7#je7 p4 #ae4 #fed ,sterzel 7#jc74 #fee ,see ,chap4 xlv4 #fef ,williamson 7#gg7 ,a4 p4 #bbf1 ,pls4 vii4-ix42 7#hj7 ,a4 p4 #eaf1 ,pl4 xx4 fig4 #af2 7#hc7 ,a4 p4 #dgj4 #feg ,thomson and ,allin 7#ab72 ,thomson 7#ac7 p4 #ad4 #feh ,penhallow 7#jj7 p4 #gf4 #fei ,white 7#jh7 ,b4 p4 #ehc4 #ffj ,seward and ,ford 7#jf7 ,b4 p4 #cda4 #ffa ,penhallow 7#jj7 p4 #fd1 fig4 #ab4 #ffb ,see page #bic4 #ffc ,gothan 7#je7 p4 #af4 #ffd ,see page #bei4 #ffe ,thomson 7#ac7 p4 #ai4 #fff ,arber 7#je7 ,b4 p4 #aia4 ,see postea1 p4 #bee4 #ffg ,an account of this wood is being published by ,miss ,holden4 #ffh ,matthew 7#aj7 p4 #gg1 ,pls4 i41 ii4 #ffi ,goeppert and ,stenzel 7#hh7 p4 #aj4 #fgj ,penhallow 7#jj7 p4 #fg4 #fga ,sterzel 7#jj72 7#jc72 7#ab74 ,see also ,goeppert 7#hj74 #fgb ,goeppert and ,stenzel 7#hh7 ,pl4 ii4 fig4 #ad4 #fgc ,witham 7#cc7 ,a4 #fgd ,scott 7#ji7 ,b4 p4 #ebh1 fig4 #aij4 ,see also ,penhallow 7#jj7 p4 #fb1 with references to literature4 #fge ,thomson 7#ac7 p4 #ai4 #fgf ,ibid4 p4 #af4 #fgg ,felix 7#hf7 ,a4 ,pl4 v4 fig4 #d4 #fgh ,white 7#jh7 ,b4 p4 #egi1 ,pl4 xiii4 #fgi ,ibid4 p4 #ehc1 ,pl4 xiv4 #fhj ,arber 7#je7 ,b4 p4 #aia1 figs4 #dj-dc4 #fha ,cri 7#hi74 #fhb ,shirley 7#ih7 p4 #ad2 ,arber 7#je7 ,b4 p4 #bja4 #fhc ,warren 7#ab74 #fhd ,dawson 7#fc74 #fhe ,penhallow 7#jj7 figs4 #ac1 #ad1 #ag4 #fhf ,arber1 ,e4 ,a4 ,n4 7#ac74 #fhg ,zeiller 7#ie7 ,b4 p4 #fai1 ,pl4 ix4 figs4 #h-ai4 #fhh ,white 7#jh7 ,b4 p4 #egg4 #fhi ,renault 7#if7 ,a4 p4 #cej2 7#ic7 ,a4 ,pl4 lxxvii4 #fij ,gothan 7#aj7 p4 #e1 ,pl4 i4 figs4 #a-c4 #fia ,nathorst 7#aa7 p4 #bbb4 #fib ,renault 7#if74 #fic ,williamson 7#gb74 #fid ,williamson 7#gd7 ,a4 p4 #fg4 #fie ,renault 7#gi7 ,b4 p4 #bid1 ,pl4 xv4 figs4 #ac-ag4 ,see also ,scott 7#ji7 ,b4 p4 #eca1 fig4 #aia4 #fif ,osborne 7#ji74 #fig ,williamson 7#gd7 ,a4 ,pl4 ix4 fig4 #ef4 #fih ,mellor and ,leslie 7#jf7 ,b4 #fii ,brongniart 7#bb7 ,a4 ,pl4 xiv4 fig4 #g4 #gjj ,renault and ,zeiller 7#ij7 ,a4 p4 #eic4 #gja ,lindley and ,hutton 7#cc7 ,a4 ,pl4 lxxxii4 #gjb ,morris 7#dj7 ,a4 ,pl4 xxviii4 fig4 #e4 #gjc ,carruthers 7#gb7 ,b4 #gjd ,goeppert 7#fe7 p4 #aeb4 #gje ,weiss1 ,c4 ,e4 7#fi7 ,b4 p4 #bja4 #gjf ,grand',eury 7#gg7 ,a4 p4 #bii2 7#ij7 ,a4 p4 #ccj4 #gjg ,zeiller 7#jj7 ,b4 p4 #baa4 #gjh ,see ,chap4 xxxv4 #gji ,lindley and ,hutton 7#cc7 ,a4 ,pl4 lxxxii42 ,carruthers 7#gb7 ,b4 p4 #g2 ,kidston 7#jc7 ,b4 p4 #ghb2 7#aa7 p4 #bce4 #gaj ,renault and ,zeiller 7#ij7 ,a4 p4 #eib1 ,pl4 lxxiii4 fig4 #ca4 #gaa ,ettingshausen 7#eb7 p4 #e1 ,pl4 v4 #gab ,renault 7#gi7 ,b4 p4 #cjd4 #gac ,bertrand1 ,c4 ,e4 7#aa74 #gad ,scott and ,maslen 7#aj72 ,scott 7#ab74 #gae ,scott 7#ji7 ,b4 pp4 #eaa1 #ebf4 #gaf ,maslen 7#aa74 #gag ,maslen 7#aa7 ,pl4 xxxiii4 figs4 #c-e4 #gah ,scott 7#ab7 p4 #ajab1 ,pls4 lxxxvii41 lxxxix4 #gai ,scott 7#ab7 p4 #ajag1 ,pls4 lxxxviii41 xc4 #gbj ,benson 7#ab74 #gba ,see page #bgj4 #gbb ,see page #acb4 #gbc ,see page #bch4 #gbd ,stopes 7#ad72 ,kidston 7#jb7 ,b4 p4 #cfc4 #gbe ,zeiller 7#jj7 ,b4 p4 #bac4 #gbf ,schimper and ,mougeot 7#dd7 ,a4 p4 #db1 ,pl4 xxi4 #gbg ,fliche 7#aj7 p4 #bah1 ,pl4 xx4 fig4 #b4 #gbh ,see postea4 #gbi ,wills1 ,l4 ,t4 7#aj71 p4 #bif1 fig4 #bf4 #gcj ,arber 7#jg7 ,pls4 xvii4-xix4 #gca ,seward 7#jd7 ,b4 p4 #aaa4 #gcb ,arber 7#ji74 #gcc ,fliche 7#aj7 p4 #bfd1 ,pl4 xxvii4 fig4 #b4 #gcd ,halle 7#aj74 #gce ,salfeld 7#ji7 ,b4 p4 #bf4 #gcf ,saporta 7#id7 ,b4 p4 #baf1 ,pl4 xxxviii4 #gcg ,velenovsk 7#he7 ,b4 p4 #a1 ,pls4 i41 iv4 #gch ,see postea4 #gci ,heer 7#gf7 ,a4 p4 #hf1 ,pl4 xxx4 fig4 #aj4 #gdj ,leuthardt 7#jc71 p4 #f1 ,pl4 i4 #gda ,fliche 7#aj7 p4 #age1 ,pls4 xvi41 xvii4 #gdb ,compter1 ,g4 7#id71 ,pl4 iv4 fig4 #i4 #gdc ,phillips 7#ga7 p4 #afi4 #gdd ,seward 7#jd7 ,b4 p4 #aaj2 ,arber1 ,e4 ,a4 ,n4 7#jg7 p4 #aag4 #gde ,zigno 7#he71 p4 #g1 ,pl4 xxvi4 #gdf ,velenovsk 7#he7 ,b4 ,pls4 i4-iii4 #gdg ,stopes and ,fujii 7#aj7 p4 #af1 ,pl4 iii4 figs4 #ad-af4 #gdh ,see postea4 #gdi ,schenk 7#ga7 p4 #bj1 ,pl4 vii4 fig4 #d4 #gej ,zeiller 7#je7 p4 #ag1 ,pl4 vii4 figs4 #h-aa4 #gea ,renault and ,zeiller 7#ij7 ,a4 p4 #fbg1 ,pl4 lxix4 figs4 #a-d4 #geb ,white 7#ii7 ,b4 p4 #bga4 #gec ,witham 7#cc7 ,a4 pp4 #cg1 #ga4 #ged ,witham 7#cj74 #gee ,goeppert 7#ha7 p4 #djc4 #gef ,endlicher 7#dg7 p4 #big4 #geg ,scott 7#jb7 p4 #cdf4 #geh ,see footnote p4 #bhh4 #gei ,scott 7#ii72 ,witham 7#cc7 ,a4 ,pls4 iii4-viii4 xvi4 #gfj ,scott 7#jb71 p4 #cdf1 ,pls4 i41 ii41 v41 vi4 #gfa ,scott 7#jb7 p4 #cee4 #gfb ,witham 7#cc7 ,a4 ,pl4 viii4 fig4 #b4 #gfc ,ibid4 p4 #ci1 ,pls4 viii41 xvi42 ,scott 7#jb7 p4 #cee1 ,pls4 ii41 vi4 #gfd ,since this chapter was written ,prof4 ,w4 ,t4 ,gordon has kindly supplied the following summary of his unpublished work on the genus ,pitys4 #8,the re-examination of ,pitys primaeva and ,p4 antiqua in the light of the structure exhibited by numerous specimens of a new species recently discovered in ,haddingtonshire has shown that all three types are similar as regards the structure of the primary wood4 ,in each case the primary cylinder is comparable with that in ,archaeopitys ,eastmanii see p4 #bij1 i4e41 there are medullary as well as circummedullary xylem-strands4 ,in certain specimens of the new species1 ,pitys ,dayii1 the bark and leaves are preserved and thus the details of leaf-trace emission from the stem have been determined4 ,the leaves are short and stout and taper gradually to a point1 quite distinct from the long1 thin1 spatulate ,cordaitean foliage4 ,the internal structure of the leaf renders it easily distinguishable from the ,cordaites type while it tends to accentuate the possible relationship of ,pitys with the ,lyginodendreae4' #gfe ,williamson 7#gh7 ,a4 p4 #ceb1 ,pl4 xxv4 figs4 #ij-ib2 ,williamson and ,scott 7#ie7 p4 #ggj2 ,seward 7#ig7 p4 #hj4 #gff ,witham 7#ca7 ,a4 #gfg ,goeppert 7#ej7 p4 #bea2 7#ha74 #gfh ,brongniart 7#di7 ,a4 #gg4 #gfi ,scott 7#jb7 p4 #ced4 #ggj ,scott and ,jeffrey 7#ad7 p4 #cde1 ,pl4 xxxi4 figs4 #ca-cf2 text-figs4 #d1 #e4 #gga ,zalessky 7#ji72 7#aa7 p4 #bi1 ,pl4 iv4 #ggb ,zalessky 7#aa7 ,pl4 iv4 fig4 #c4 #ggc ,scott 7#ab7 p4 #ajbd4 #ggd ,elkins and ,wieland 7#ad74 #gge ,penhallow 7#jj7 pp4 #fd1 ,pl4 xii4 #ggf ,zalessky 7#aa7 p4 #ac1 figs4 #a-d4 #ggg ,see page #bie4 #ggh ,zalessky 7#aa7 p4 #bh4 #ggi ,williamson 7#hj7 ,a4 p4 #eaf1 ,pl4 xx4 fig4 #fj4 #ghj ,scott 7#jb7 p4 #ceg1 ,pls4 ii41 vi4 #gha ,scott 7#ab7 p4 #ajbh4 #ghb ,goeppert 7#de7 p4 #aa1 ,pls4 xxix4-xxxv42 ,zalessky 7#aa74 #ghc ,goeppert and ,stenzel 7#hh7 p4 #cc1 ,pls4 v41 vi4 #ghd ,kraus in ,schimper 7#gb7 ,a4 p4 #cha4 #ghe ,seward 7#ad7 p4 #ag1 ,pls4 iv4-viii4 #ghf ,scott 7#ab74 #ghg ,see page #age4 #ghh ,de ,bary 7#hd7 ,a4 p4 #dib2 ,grossenbacher 7#ae74 #ghi ,see ,scott1 ,nature1 ,august #bf1 #aiae4 #gij ,see ,vol4 ii4 p4 #ef4 #gia ,oliver 7#jf7 p4 #gbf4 #gib ,hooker and ,binney 7#ee74 #gic ,oliver 7#jc74 #gid ,worsdell 7#je7 p4 #eh2 ,salisbury 7#ad7 p4 #fg4 #gie ,brongniart 7#ha7 p4 #ca4 #gif ,for an account of the work of this author see ,lang in ,oliver 7#ac7 p4 #agh4 #gig ,see ,scott 7#ji7 ,b4 p4 #edc4 #gih ,mirande 7#je74 #gii ,for definition of ,cardiocarpus1 see page #cch4 #hjj ,see page #be4 #hja ,solms-,laubach 7#ia7 ,a4 p4 #aah4 #hjb ,goeppert 7#fe7 p4 #agg1 ,pl4 xxvi4 figs4 #bg1 #bh4 #hjc ,williamson 7#gg7 ,b4 p4 #bfb4 #hjd ,zeiller 7#hh7 ,a4 p4 #fdb4 #hje ,brongniart 7#gd74 #hjf ,brongniart 7#ha74 #hjg ,oliver 7#jd7 ,b4 p4 #chi4 #hjh ,affourtit and ,la ,rivire 7#ae74 #hji ,nathorst 7#ad7 p4 #cb4 #haj ,see page #agc4 #haa ,salisbury 7#ad7 p4 #ga4 #hab ,salisbury 7#ad74 #hac ,oliver 7#jd7 ,b4 p4 #cib4 #had ,oliver 7#jg74 #hae ,arber1 ,a4 7#aj7 p4 #eje4 #haf ,see ,chapter xxxi4 #hag ,oliver and ,salisbury 7#aa74 #hah ,salisbury 7#ad7 p4 #fg4 #hai ,oliver 7#ji7 p4 #ii4 #hbj ,nathorst 7#ad7 p4 #bi4 #hba 1 to blow2 1 a bladder4 #hbb ,williamson 7#gf7 p4 #afj2 7#ag7 ,b4 p4 #bda1 ,pl4 xi4 figs4 #gg1 #gh2 ,pl4 xii4 fig4 #gi4 #hbc ,oliver 7#ji72 ,oliver and ,salisbury 7#aa7 passim2 ,salisbury 7#ad7 p4 #gd4 #hbd ,williamson 7#hj7 ,a4 ,pl4 xvii4 figs4 #bd-bh2 7#hc7 ,a4 ,pl4 xxxi4 fig4 #bg 7called in this case ,sporocarpon anomalum1 no doubt a slip of the pen74 #hbe ,oliver 7#ji7 p4 #ge4 #hbf ,williamson 7#gf7 p4 #afj4 #hbg ,oliver 7#ji7 p4 #ajf4 #hbh ,lang 7#jj7 p4 #bhh4 #hbi ,burlingame 7#ae7 p4 #ai4 #hcj ,gordon1 ,w4 ,t4 7#aj74 #hca 1 a cone4 #hcb ,williamson 7#gg7 ,b4 p4 #bda1 ,pls4 xi41 xii4 #hcc ,page #gi4 #hcd ,oliver and ,salisbury 7#aa74 #hce ,for a detailed account of the plinth see ,oliver and ,salisbury 7#aa74 #hcf ,page #bg4 #hcg ,page #ee4 #hch ,renault 7#hd7 ,pls4 xix4-xxii4 #hci ,saporta and ,marion 7#he7 p4 #aha4 #hdj ,oliver and ,salisbury 7#aa74 #hda ,renault 7#if7 ,a4 p4 #he1 ,pl4 xlii4 #hdb ,renault and ,zeiller 7#hh7 ,a4 p4 #fdj1 ,pls4 #gb1 #hb4 #hdc ,grand',eury 7#ij7 ,a4 ,pl4 vi4 fig4 #f4 #hdd ,depape and ,carpentier 7#ac7 ,pl4 xii4 figs4 #a-c4 #hde ,kidston 7#ij7 p4 #fd4 #hdf ,oliver 7#jb7 p4 #adf4 #hdg ,kershaw 7#ji74 #hdh ,oliver 7#jd7 ,b4 p4 #cgf4 #hdi ,renault 7#if7 ,a4 p4 #bgb4 #hej ,arber1 ,e4 ,a4 ,n4 7#ad7 p4 #ajc1 ,pl4 viii4 figs4 #dh-ej4 #hea ,brongniart 7#ha7 ,pl4 ,b4 fig4 #c4 #heb ,grand',eury 7#gg7 ,a4 ,pl4 xv4 fig4 #a4 #hec ,newberry 7#gc74 #hed ,ibid4 ,pl4 xlii4 fig4 #h4 #hee ,page #abc4 #hef ,oliver 7#jd7 ,b4 ,see also ,renault 7#if7 ,a4 p4 #cih4 #heg ,zeiller 7#hh7 ,a4 p4 #feb1 ,pl4 #id1 fig4 #ag4 #heh ,salisbury 7#ad74 #hei ,brongniart 7#gd7 p4 #beb1 ,pl4 xxii4 figs4 #f-h4 #hfj ,oliver 7#jd7 ,b4 p4 #cia4 #hfa ,renault 7#if7 ,a4 p4 #djd4 #hfb ,kidston 7#ad7 p4 #aeg4 #hfc 1 a plate or fold4 #hfd ,brongniart 7#gd7 p4 #bec1 ,pl4 xxii4 figs4 #i-aa2 7#ha7 p4 #bf4 #hfe ,ibid4 p4 #bed1 ,pl4 xxii4 figs4 #ab-ad2 7#ha7 p4 #bf4 #hff ,williamson 7#gg7 ,b4 p4 #bec4 #hfg ,see page #cef4 #hfh ,p4 ,bertrand 7#ac7 ,pl4 vii4 #hfi ,brongniart 7#gd7 p4 #bee1 ,pl4 xxiii4 figs4 #a-c2 7#ha7 p4 #bg1 ,pl4 ,c1 figs4 #a-c4 #hgj ,arber1 ,e4 ,a4 ,n4 7#ad7 p4 #ajb1 ,pl4 vii4 figs4 #ch-da4 #hga ,kidston 7#ad7 p4 #aeh1 ,pl4 x4 figs4 #f1 #g2 ,pl4 xiv4 figs4 #e-i4 #hgb ,brongniart 7#gd7 p4 #bdi1 ,pl4 xxii4 figs4 #d1 #e2 7#ha7 ,pls4 xvii4-xxi4 #hgc ,renault 7#if7 ,a4 p4 #chi1 ,pls4 #hc1 #hd4 #hgd ,oliver 7#jb74 #hge ,grand',eury 7#jd74 #hgf ,grand',eury 7#ij7 ,a4 ,pl4 viii4 fig4 #c2 7#gg7 ,a4 ,pl4 xvi4 fig4 #e4 #hgg ,renault and ,zeiller 7#hh7 ,a4 ,pl4 #gc4 #hgh ,zeiller 7#jf7 ,b4 p4 #bbi4 #hgi ,kidston 7#ib7 p4 #h4 #hhj ,arber1 ,e4 ,a4 ,n4 7#ad7 p4 #ia1 ,pl4 vii4 fig4 #bh4 #hha ,see page #cfd4 #hhb ,white 7#ii7 ,b4 p4 #bfg2 ,lesquereux 7#gi7 ,a4 ,pl4 #he1 fig4 #ba4 #hhc ,brongniart 7#gd7 p4 #bei1 ,pl4 xxiii4 figs4 #ab-ae2 7#ha7 p4 #bi1 ,pl4 xvi4 #hhd ,renault 7#hj74 #hhe ,oliver 7#jd7 ,b4 #hhf ,russow 7#gb7 ,pls4 iii41 iv4 #hhg 1 a crown4 #hhh ,oliver 7#jd7 ,b4 p4 #cie4 #hhi ,brongniart 7#ha7 ,pl4 xvi4 figs4 #d1 #f4 #hij ,ibid4 p4 #cgc1 ,pl4 xlii4 figs4 #ag-bj2 xliv4 figs4 #cf-dc4 #hia 1 a ridge4 #hib ,brongniart 7#gd7 p4 #bef1 ,pl4 xxiii4 figs4 #f-h2 7#ha7 ,pl4 ,c1 figs4 #f-h4 #hic ,oliver 7#jd7 ,b4 ,pl4 ii4 figs4 #e-aj2 7#jg7 fig4 #a4 #hid ,scott and ,maslen 7#jg7 ,pl4 xiii4 fig4 #ai4 #hie ,salisbury 7#ad74 #hif 1 a bell4 #hig ,brongniart 7#gd7 p4 #beg1 ,pl4 xxiii4 figs4 #i-ab2 7#ha7 p4 #bh1 ,pl4 ,c1 figs4 #i-ab4 #hih ,renault 7#ic7 ,a4 ,pl4 lxxxvii42 7#if7 ,a4 p4 #cic4 #hii ,renault and ,zeiller 7#hh7 ,a4 p4 #fei1 ,pl4 #hc1 figs4 #aj-bf4 #ijj ,grand',eury 7#gg7 ,a4 p4 #ahd1 ,pl4 xv4 fig4 #e2 7#ij7 ,a4 p4 #caa1 ,pl4 iii4 fig4 #f4 #ija ,zeiller 7#jf7 ,b4 p4 #bbg4 #ijb ,see also ,grand',eury 7#je7 ,b4 #ijc ,brongniart 7#gd7 p4 #bfj1 ,pl4 xxiii4 pp4 #af-ah2 7#ha7 p4 #cj4 #ijd ,renault #if ,a4 p4 #bgb4 #ije ,brongniart 7#gd7 p4 #bef1 ,pl4 xxiii4 figs4 #d1 #e2 7#ha7 p4 #bg1 ,pl4 ,c1 figs4 #d1 #e4 #ijf 1 wool4 #ijg ,grand',eury 7#ij7 ,a4 p4 #cjh1 ,pls4 iv4 fig4 #ab1 vi4 fig4 #e4 #ijh ,see page #bfd4 #iji ,brongniart 7#bh7 ,a4 p4 #hg4 #iaj ,brongniart 7#gd7 p4 #bde 7#ha74 #iaa ,geinitz 7#fb7 p4 #aej2 ,kidston 7#aa7 p4 #bdj2 ,geinitz 7#ee7 ,a4 ,pl4 xxi4 figs4 #g-af4 #iab ,kidston 7#id7 ,b4 p4 #bfc4 #iac ,renault 7#hj71 p4 #ajb4 #iad ,fiedler 7#eg7 p4 #bia4 #iae ,brongniart 7#ha7 ,pls4 iv41 v4 #iaf ,bertrand1 ,c4 ,e4 7#jh74 #iag ,renault 7#if7 ,a4 p4 #che4 #iah ,bertrand1 ,c4 ,e4 7#jh74 #iai ,fiedler 7#eg7 p4 #bhh1 ,pl4 xxviii4 #ibj ,schenk 7#hj7 p4 #ffj4 #iba ,ward 7#hh7 p4 #hjb4 #ibb ,goeppert 7#fe7 p4 #agg1 ,pl4 xxviii4 figs4 #aj1 #aa4 #ibc ,ibid4 fig4 #ai4 #ibd ,heer 7#gg7 ii4 ,pl4 xix4 ,see also ,nathorst 7#hf7 ,pl4 xxv4 figs4 #aj-ad4 #ibe ,arber1 ,e4 ,a4 ,n4 7#ad7 p4 #ig4 #ibf ,arber1 ,e4 ,a4 ,n4 7#ji7 ,pl4 i4 fig4 #e4 #ibg ,feistmantel 7#gi7 #ibh ,schenk 7#hc7 ,a4 ,pl4 xliv4 fig4 #h4 #ibi ,seward 7#ig7 ,a4 #icj ,white 7#jh7 ,b4 #ica ,feistmantel 7#ij7 ,a4 p4 #afd4 #icb ,geinitz 7#hj7 p4 #bb1 ,pl4 iii4 figs4 #aa-ae4 #icc ,weiss1 ,c4 ,e4 7#gb7 p4 #bjh4 #icd ,see page #ada4 #ice ,white 7#jh7 ,b4 p4 #efc4 ,see also ,vol4 ii4 p4 #eag4 #icf ,goeppert 7#fe7 p4 #adf1 ,pl4 xxvi4 fig4 #e4 #icg ,heer 7#gg7 ii4 ,pl4 xiv4 #ich ,see page #cde4 #ici ,brongniart 7#ha7 p4 #bj1 ,pl4 ii4 #idj ,bertrand1 ,c4 ,e4 7#jh72 7#jh74 #ida ,bertrand1 ,c4 ,e4 7#jh74 #idb ,this name has been used for a section of a genus of recent ,umbelliferae but not as a generic name 7,de ,candolle's #8,prodromus1' ,pars iv4 p4 #aje1 #ahcj74 #idc ,bertrand 7#jh7 p4 #ded2 7#jh7 p4 #cib4 #idd ,brongniart 7#ha7 ,pls4 iv4 v4 #ide ,schimper 7#gb7 ,a4 p4 #bjh4 #idf ,brongniart 7#ha7 ,pl4 iii42 ,bertrand1 ,c4 ,e4 7#jh74 #idg 1 a rod4 #idh ,berger 7#dh7 p4 #bj1 ,pl4 i4 fig4 #h4 #idi ,renault and ,zeiller 7#hh7 ,a4 p4 #fce4 #iej ,bertrand1 ,p4 7#ac74 #iea ,arber 7#ad7 p4 #ajc4 #ieb ,see page #aaf4 #iec ,arber 7#ad7 p4 #hg4 #ied ,zeiller 7#ib7 ,a4 ,pl4 xv4 fig4 #aa4 #iee ,arber 7#ad7 ,pl4 vii4 fig4 #ba4 #ief ,in selecting a generic name for a fossil plant or part of a plant it has not been the universal practice to avoid the use of a designation previously employed for a recent plant4 ,it is clearly in accordance with the ,rules adopted by the ,international ,botanical ,congress and with general convenience to avoid the employment of the same name for two different generic types even if one is known only in a fossil state4 ,my attention has been called by ,mr ,w4 ,n4 ,edwards of the ,british ,museum to the fact that the names ,platyspermum1 ,microspermum1 and ,pterospermum recently proposed by ,dr ,arber for ,palaeozoic seeds have previously been given to recent flowering plants4 ,though ,i have often neglected to consult the ,index ,kewensis and the ,genera ,siphonogamarum before proposing a #8new' generic term1 ,i fully recognise the importance of avoiding the employment of names in current use or names which have #8lapsed into synonymy#iff4' #ieg ,see page #cfa4 #ieh ,brongniart 7#gd7 p4 #bdf2 7#ha7 p4 #ba1 ,pls4 ix4-xi4 #iei ,bertrand1 ,c4 ,e4 7#jg74 #ifj ,grand',eury 7#je74 #ifa ,kidston 7#ad7 ,pl4 xvi4 figs4 #f-h4 #ifb ,lesquereux 7#hj7 ,a4 p4 #egd4 #ifc ,white 7#ii7 ,b4 p4 #bfg4 #ifd ,grand',eury 7#gg7 ,a4 ,pl4 xv4 #ife ,renault 7#ic7 ,a4 ,pl4 lxxxvi4 #iff ,rgles internationales de la nomenclature botanique adoptes par le ,cong4 ,internat4 ,bot4 de ,vienne1 #aije1 etc4 ,t4 ,briquet1 ,jena1 #aiab1 p4 #cg4 #ifg ,see page #cad4 #ifh ,arber1 ,a4 7#aj74 #ifi 1 a ,persian cap4 #igj ,williamson 7#gg7 ,b4 p4 #beg1 ,pls4 xv4 xvi4 #iga ,bertrand1 ,c4 ,e4 7#jh74 #igb ,brongniart 7#gd7 p4 #bdg1 ,pl4 xxi4 figs4 #ab-ad2 7#ha7 p4 #ba1 ,pl4 ,a4 fig4 #ab2 ,pl4 xiv2 ,renault 7#hj7 p4 #ajf1 ,pl4 xv4 figs4 #ab1 #ac2 ,grand',eury 7#gg7 ,a4 p4 #bci1 ,pl4 xxvi4 fig4 #bg4 #igc ,bertrand1 ,c4 ,e4 7#jg74 #igd ,brongniart 7#gd7 p4 #bdh1 ,pl4 xxi4 fig4 #ag2 7#ha7 p4 #bb1 ,pl4 ,a4 fig4 #ag2 ,pl4 vi4 #ige ,bertrand1 ,c4 ,e4 7#jg7 compares ,leptocaryon with ,diplotesta as regards various structural features4 #igf ,renault 7#hj7 p4 #ajh4 #igg ,brongniart 7#gd7 p4 #bdi1 ,pl4 xxi4 figs4 #ah-bj2 7#ha7 p4 #bc1 ,pl4 ,a4 figs4 #ah-bj2 ,pl4 xv4 #igh ,oliver 7#jc7 p4 #deg4 #igi ,bertrand1 ,c4 ,e4 7#jg74 #ihj ,bertrand1 ,c4 ,e4 7#jg74 #iha ,brongniart 7#gd7 p4 #bdg4 #ihb 1 elegant4 #ihc ,bertrand1 ,c4 ,e4 7#ji74 #ihd ,dawson 7#ff7 ,a4 p4 #afe1 ,pl4 xii4 fig4 #gd2 ,zeiller 7#jf7 ,b4 p4 #bbf2 ,kidston 7#aa7 p4 #bcf4 #ihe ,zeiller 7#hh7 ,a4 p4 #fdd4 #ihf ,white 7#ii7 ,b4 p4 #bff1 ,pls4 lxi4 fig4 #ab1 lxxii4 fig4 #c4 #ihg ,weiss1 ,c4 ,e4 7#gb7 ,pl4 xviii4 #ihh ,kidston 7#id7 ,b4 ,pl4 vi4 fig4 #c2 7#jb7 ,b4 ,pl4 lviii4 figs4 #e1 #f4 #ihi ,lesquereux 7#hj7 ,a4 ,pl4 lxxxv4 fig4 #ea4 #iij ,helmhacher 7#ga74 #iia ,zeiller 7#ib7 ,a4 ,pl4 xv4 figs4 #i1 #aj4 #iib ,geinitz 7#ge7 ,pl4 i4 figs4 #aj1 #aa2 ,weiss1 ,c4 ,e4 7#gi7 ,pl4 iii4 figs4 #ag-ai4 #iic ,potoni 7#ic7 ,a4 ,pl4 xxxii4 figs4 #ab1 #ac4 #iid ,stopes 7#ad7 ,pl4 xxv4 fig4 #fh4 #iie ,arber 7#ad7 ,pl4 vi4 figs4 #ai1 #bj2 7#ad7 ,pl4 xi4 fig4 #e4 #iif ,for synonymy1 see ,kidston 7#aa7 p4 #bch1 ,pl4 xxii4 figs4 #c1 #c;a4 #iig ,fiedler 7#eg7 p4 #bia4 #iih ,stopes 7#ad7 p4 #hi1 ,pls4 xxi4-xxiii4 #iii ,andrews 7#ge7 p4 #dbe1 ,pl4 xlvi4 fig4 #b4 #ajjj ,kidston 7#aa7 p4 #bci1 ,pl4 xii4 fig4 #a4 #ajja ,dawson 7#ga7 ,a4 ,pl4 xix4 fig4 #bai2 ,stopes 7#ad7 p4 #ib4 #ajjb ,fiedler 7#eg7 ,pl4 xxviii4 fig4 #cf4 #ajjc ,white 7#jh7 ,b4 p4 #efg1 ,pl4 x4 fig4 #aa4 #ajjd ,newberry 7#gc7 ,pl4 xliii4 fig4 #h2 ,lesquereux 7#hj7 ,a ,pl4 lxxxv4 figs4 #cf1 #cg4 #ajje ,lesquereux 7#hd7 ,a ,pl4 cix4 figs4 #ac1 #ae4 #ajjf ,seward 7#ig7 ,a p4 #ccb2 ,arber 7#je7 ,b4 pp4 #bjf1 #bjg4 #ajjg ,white 7#jh7 ,b4 p4 #eei1 ,pl4 x4 figs4 #e-h4 #ajjh ,vol4 ii4 p4 #eag4 #ajji ,seward and ,leslie 7#jh7 ,b4 #ajaj ,zeiller 7#jb7 ,b4 p4 #cg1 ,pl4 vii4 figs4 #g1 #h2 ,arber 7#je7 ,b4 p4 #bje1 fig4 #dd4 #ajaa ,lesquereux 7#hj7 ,a4 ,pl4 #he1 figs4 #cd1 #ce4 #ajab ,feistmantel 7#gi7 p4 #cj2 7#ha7 p4 #ei1 ,pl4 xxx4 fig4 #ad2 7#hb7 p4 #dc1 ,pl4 xv4 figs4 #e-ab4 #ajac ,arber 7#je7 ,b4 p4 #bje4 #ajad ,vol4 ii4 p4 #ejj4 #ajae ,geinitz 7#ga7 p4 #agd1 ,pl4 iii4 figs4 #aj1 #aa4 #ajaf ,ibid4 7#ee7 ,a4 ,pl4 xxi42 ,zeiller 7#hh7 ,a4 ,pl4 xciv4 fig4 #ac2 7#jf7 ,b4 p4 #bbd2 ,kidston 7#aa7 p4 #bdj2 ,arber 7#ad7 p4 #ajj4 #ajag ,boulay 7#gi7 p4 #cd4 #ajah ,zeiller 7#hh7 ,a4 ,pl4 xciv4 fig4 #ab2 ,kidston 7#aa7 ,pl4 v4 figs4 #e-g2 ,arber 7#ad7 p4 #ajj4 #ajai ,berger 7#dh7 ,pl4 ii4 figs4 #ai1 #bj4 #ajbj ,renault and ,zeiller 7#hh7 ,a4 ,pl4 lxxii4 fig4 #c4 #ajba ,ibid4 p4 #fdi4 #ajbb ,ibid4 ,pl4 lxxii4 figs4 #ec-ee4 #ajbc ,williamson 7#gg7 ,b4 p4 #bec1 ,pl4 xvi4 figs4 #aae a1 #aae b4 #ajbd ,kidston 7#ad7 p4 #afe4 #ajbe ,bertrand1 ,p4 7#ac7 ,pl4 vii4 #ajbf ,renault and ,zeiller 7#hh7 ,a4 p4 #fea1 ,pl4 lxxii4 fig4 #ef4 #ajbg ,grand',eury 7#gg7 ,a4 p4 #ahe1 ,pls4 xv41 xvi4 #ajbh ,arber 7#ad7 pp4 #ic1 #ajd1 ,pl4 viii4 figs4 #ea1 #eb4 #ajbi ,kidston 7#ad7 p4 #aeg1 ,pl4 xiv4 figs4 #a1 #b4 #ajcj ,see page #cba4 #ajca ,arber1 loc4 cit4 p4 #ajb4 #ajcb ,kidston1 loc4 cit4 p4 #aeh4 #ajcc ,heer 7#gg7 i4 p4 #ai1 ,pl4 v4 figs4 #a-aa4 #ajcd ,nathorst 7#id7 ,a4 p4 #dh1 ,pl4 iv4 figs4 #g1 #h4 #ajce ,young 7#fi7 ,pl4 iv4 figs4 #i1 #aj2 7#gf7 p4 #cf4 #ajcf ,zalessky 7#je74 #ajcg ,nathorst 7#ad7 p4 #bc1 ,pl4 xv4 figs4 #dd-ea4 #ajch ,lindley and ,hutton 7#cg7 ,a4 ,pl4 #bbj4 #ajci ,zalessky 7#je74 #ajdj ,for this information ,i am indebted to ,dr ,kidston4 #ajda ,nathorst 7#ad7 p4 #cb1 ,pl4 xv4 fig4 #eh4 #ajdb ,zalessky 7#je74 #ajdc ,nathorst 7#ad7 p4 #bg1 ,pl4 v4 figs4 #ai-bb2 ,pl4 xv4 fig4 #ajdd ,heer 7#gg7 i4 p4 #bd1 ,pl4 v4 figs4 #ah-bb4 #ajde ,nathorst 7#ad7 p4 #ce1 ,pl4 xv4 figs4 #gg-hb4 #ajdf ,grand',eury 7#gg7 ,a4 ,pl4 xvi4 figs4 #b-d4 #ajdg ,brongniart 7#bh7 ,a4 p4 #acg4 #ajdh ,grand',eury 7#gg7 ,a4 p4 #ahd1 ,pl4 xv4 fig4 #c4 #ajdi ,see page #ccj4 #ajej ,sternberg 7#ch7 ,a4 ,pl4 x4 fig4 #c4 #ajea ,lindley and ,hutton 7#cg7 ,a4 ,pl4 #bbj4 #ajeb ,zalessky 7#je7 p4 #aai4 #ajec ,renault and ,zeiller 7#hh7 ,a4 p4 #feb1 ,pl4 lxxii4 figs4 #fc-ff2 ,renault 7#if7 ,a4 p4 #djj2 7#ic7 ,a4 ,pl4 lxxxiv4 fig4 #c4 #ajed ,arber 7#ad7 p4 #ie1 ,pl4 vi4 fig4 #aa4 #ajee ,kidston 7#hh7 ,b4 ,pl4 xxiii4 fig4 #d4 #ajef ,nathorst 7#ad7 p4 #bh4 #ajeg ,ibid4 ,pl4 xv4 figs4 #ec1 #ed4 #ajeh ,williamson 7#gg7 ,b4 p4 #bdf1 ,pl4 xiii4 figs4 #hh-ic4 #ajei ,nathorst 7#ad7 p4 #cc4 ,pl4 xv4 figs4 #fi1 #gj4 #ajfj ,see page #cjd4 #ajfa ,nathorst 7#ad7 p4 #cc4 #ajfb ,seward 7#ie7 ,a4 p4 #aja4 #ajfc ,kidston 7#ib7 p4 #h2 ,arber 7#ad7 ,pl4 vii4 fig4 #bh4 #ajfd ,kidston 7#hf7 ,b4 ,pl4 iii4 figs4 #g a-c2 ,berger 7#dh7 ,pl4 ii4 figs4 #cj1 #ca4 #ajfe ,see postea4 #ajff ,arber 7#ad7 pp4 #ij1 #ajj1 ,pl4 vii4 figs4 #bb-bg4 #ajfg ,carpentier 7#aa7 p4 #g1 ,pl4 xiv4 fig4 #c4 #ajfh ,geinitz 7#fb7 p4 #ade1 ,pl4 xxv4 figs4 #g-i2 ,goeppert 7#fd7 ,a4 p4 #ade4 #ajfi ,nathorst 7#jb7 p4 #c4 #ajgj ,carruthers 7#gj7 p4 #fid4 #ajga ,nathorst 7#jb7 p4 #bc4 #ajgb ,ibid4 7#ji7 pp4 #ba1 #bc4 #ajgc ,thomas and ,bancroft 7#ac7 p4 #aif4 #ajgd ,buckland 7#bg7 ,proc4 ,geol4 ,soc4 ,london1 ,vol4 i4 ,no4 #h1 p4 #hj2 7#bh74 #ajge ,brongniart 7#bh7 ,a4 p4 #if4 #ajgf ,ibid4 7#di7 ,a4 p4 #ei4 #ajgg ,carruthers 7#gj7 p4 #fgh4 #ajgh ,buckland 7#cg7 p4 #dif1 ,pls4 lx41 lxi4 #ajgi ,ibid4 7#bh71 ,pl4 lxi4 fig4 #a4 ,a specimen in the ,oxford ,museum may be the original of ,buckland's figure4 #ajhj ,carruthers 7#gj74 #ajha ,pomel 7#di7 p4 #af4 #ajhb ,carruthers 7#gj7 p4 #fij4 #ajhc ,saporta 7#ge7 ,a4 pp4 #bef1 #bfe1 ,pls4 #aah1 #aai4 #ajhd ,lindley and ,hutton 7#ce7 ,a4 ,pl4 #adc4 #ajhe ,ward 7#id74 #ajhf ,fliche and ,zeiller 7#jd74 #ajhg ,saporta 7#ge7 ,a4 p4 #bgf1 ,pl4 #abj4 #ajhh ,lignier 7#ja74 #ajhi ,ibid4 7#ac7 p4 #ic4 #ajij ,solms-,laubach 7#ia74 #ajia ,seward 7#ie7 ,a4 p4 #aci4 #ajib ,ibid4 7#jd7 ,b4 p4 #dd4 #ajic ,wieland 7#jf74 #ajid ,stopes 7#ae7 p4 #cji4 #ajie ,buckland 7#cg7 ,a4 ,vol4 ii4 p4 #ih1 ,pl4 lxi4 fig4 #a4 #ajif ,ibid4 7#bh7 ,pl4 xlix4 #ajig ,seward 7#ie7 ,a4 p4 #aff4 #ajih ,stopes 7#ae7 p4 #cji4 #ajii ,see page #dbe4 #aajj ,wieland 7#jf7 ,pls4 vi4-xiii4 #aaja ,ibid4 7#ab7 p4 #hh1 fig4 #aj4 #aajb ,wieland 7#jf7 p4 #fc1 fig4 #cc4 #aajc ,see ,wieland 7#jf7 for additional facts and illustrations4 #aajd ,see page #dag4 #aaje ,wieland 7#jf7 p4 #gf2 ,capellini and ,solms-,laubach 7#ib7 ,pl4 v4 fig4 #f4 #aajf ,capellini and ,solms-,laubach 7#ib7 ,pl4 v4 fig4 #b4 #aajg ,see ,chapter xxxix4 #aajh ,see page #dhi4 #aaji ,wieland 7#ii72 7#jf7 p4 #hg4 #aaaj ,wieland in ,ward 7#je7 ,b4 p4 #bjj1 ,pl4 lxiii4 #aaaa ,wieland 7#ad74 #aaab ,the flowers are frequently described as protandrous but1 as ,dr ,scott pointed out to me1 we have no definite evidence on this point4 #aaac ,wieland 7#aa7 p4 #acd2 ,coulter and ,chamberlain 7#aj7 p4 #fg1 fig4 #ee4 #aaad ,wieland 7#jf7 p4 #afj1 fig4 #hd4 #aaae ,ibid4 7#ad74 #aaaf ,see also ,wieland 7#aa7 p4 #aeb1 fig4 #i4 #aaag ,capellini and ,solms-,laubach 7#ib72 ,ward 7#if7 p4 #eje4 #aaah ,ward 7#if7 ,pl4 civ4 #aaai ,ward 7#jd72 ,wieland 7#jh74 #aabj ,fontaine 7#hi7 ,b4 p4 #aic1 ,pls4 clxxiv4-clxxx4 #aaba ,ward 7#id74 #aabb ,for an account of the stratigraphy1 see ,ward 7#id74 #aabc ,ward 7#je7 ,b4 #aabd ,ibid4 7#jj74 #aabe ,coemans 7#ff74 #aabf ,wieland 7#ac74 #aabg ,carruthers 7#gj74 #aabh ,lignier 7#id74 #aabi ,see page #cie4 #aacj ,wieland 7#jf74 #aaca ,buckland 7#cg74 #aacb ,see page #ddh4 #aacc ,carruthers 7#gj74 #aacd ,ibid4 p4 #fih2 for other references1 see ,seward 7#ie7 ,a4 #aci4 #aace ,carruthers 7#gj7 ,pls4 lvii41 lviii4 #aacf ,capellini and ,solms-,laubach 7#ib7 ,pl4 v4 fig4 #b4 #aacg ,see also ,stopes 7#ae7 p4 #dg4 #aach ,chamberlain 7#ac74 ,see ,chapter xxviii41 page #f4 #aaci ,solms-,laubach 7#ia74 #aadj ,see page #ddi4 #aada ,scott 7#ji7 ,b1 p4 #ega4 #aadb ,it is possible that1 as ,scott suggests1 a small patch of endosperm is represented in a seed of this species figured by him4 ,scott 7#ji7 ,b4 p4 #efi1 fig4 #bjc1 ,d1 e4 #aadc ,see page #cif4 #aadd ,the age was at first believed to be ,oxfordian1 but ,lignier subsequently 7#ji7 referred the rocks to a ,lower ,cretaceous horizon4 #aade ,morire 7#fi74 #aadf ,saporta and ,marion 7#ha7 ,a42 7#he7 p4 #bdd2 ,saporta 7#ia7 p4 #afh1 ,pls4 #adh1 #adi4 #aadg ,lignier 7#id72 7#jd72 7#ji72 7#aa74 #aadh ,saporta 7#ge7 ,a4 p4 #cbh1 ,pl4 #abc4 #aadi ,lignier 7#id7 p4 #eg2 7#ab74 #aaej ,lignier 7#aa74 #aaea ,berridge 7#aa72 ,thoday1 ,m4 ,g4 7#aa74 #aaeb ,lignier 7#jd74 #aaec ,solms-,laubach 7#ia74 #aaed ,pearson 7#ji74 #aaee ,wettstein 7#aa7 p4 #chh4 #aaef ,worsdell 7#jj74 #aaeg ,mc,bride 7#ic74 #aaeh ,ward 7#ih7 p4 #bje4 #aaei ,wieland 7#jf7 p4 #ahe4 ,see ,wieland's description for further details4 #aafj ,ward 7#ih7 p4 #bjh4 #aafa ,wieland 7#jf7 ,pls4 vii4-ix41 xii41 xiii4 #aafb ,ibid4 ,pl4 xix4 fig4 #e4 #aafc ,ibid4 passim2 7#ab74 #aafd ,wieland 7#ad74 #aafe ,this subject is more fully dealt with by ,wieland in the ,volume published since the above was written ,wieland 7#af74 #aaff ,goeppert 7#ec74 #aafg ,solms-,laubach 7#ia7 ,a4 p4 #ajj4 #aafh ,schuster 7#aa74 ,an excellent photograph of the stem is reproduced in this paper4 #aafi ,wieland 7#jh7 p4 #if4 #aagj ,raciborski 7#ib74 #aaga ,seward 7#ig7 ,a4 #aagb ,wieland 7#jf7 ,pl4 xix4 fig4 #e4 #aagc ,seward 7#ig7 ,a4 figs4 #c1 #d1 pp4 #bd1 #cb4 #aagd ,lignier 7#ja74 #aage ,lignier 7#ja74 #aagf ,morire 7#fi74 #aagg ,saporta 7#ge7 ,a4 ,pl4 l4 #aagh ,ward 7#id7 p4 #hg2 7#ih7 p4 #baf4 #aagi ,wieland 7#jf7 p4 #gi1 ,pl4 xiv4 #aahj ,chamberlain 7#ji74 #aaha ,fliche and ,zeiller 7#jd7 p4 #ghi1 ,pl4 xix4 #aahb ,saporta 7#ge7 ,a4 p4 #bfb1 ,pl4 #aah4 #aahc ,ward 7#ii7 ,b4 p4 #fci1 ,pls4 clvi41 clvii4 #aahd ,lindley and ,hutton 7#ce7 ,a4 ,pl4 #adc4 7,i have not seen the actual specimen4--,a4 ,c4 ,s47 #aahe ,ward 7#jj71 ,pls4 xiv4-xxi4 #aahf ,ibid4 7#je7 ,b4 p4 #aih1 ,pls4 xlvi4-lxiii4 #aahg ,wieland 7#jf7 p4 #aja4 #aahh ,fliche 7#if7 p4 #dh1 ,pl4 v4 figs4 #b1 #c2 ,pl4 xiv4 fig4 #a4 #aahi ,ibid4 ,pl4 v4 fig4 #c4 #aaij ,stopes 7#ae7 p4 #bdg1 ,pls4 xxiii4-xxv41 text-figs4 #gb-ge4 #aaia ,solms-,laubach 7#jd7 p4 #ab1 ,pl4 ii4 figs4 #e1 #f4 #aaib ,young and ,bird 7#bb7 ,a4 ,for a fuller account of the history of our knowledge of ,williamsonia1 see ,seward 7#ie7 ,a4 p4 #adf4 #aaic ,williamson 7#dj7 p4 #bcj4 #aaid ,yates 7#ee74 #aaie ,leckenby1 ,a4 7#fd74 ,see also ,seward 7#jj7 ,b4 p4 #aij4 #aaif ,williamson 7#gj74 #aaig ,carruthers 7#gj74 #aaih ,saporta 7#ia74 #aaii ,seward 7#ig74 #abjj ,wieland 7#aa74 #abja ,wieland 7#ac74 #abjb ,nathorst 7#ac74 #abjc ,see page #dhj4 #abjd ,williamson 7#gj7 ,pl4 liii4 fig4 #e2 ,seward 7#ig74 #abje ,saporta 7#ge7 ,a4 ,pl4 xi4 fig4 #a4 #abjf ,ibid4 ,pl4 xv4 #abjg ,wieland 7#aa7 p4 #ddh1 fig4 #f4 #abjh ,seward 7#ie7 ,a4 p4 #adf4 #abji ,nathorst 7#ji7 7#aa74 #abaj ,lignier 7#jg74 #abaa ,saporta 7#ia7 ,pl4 #bdh4 #abab ,nathorst 7#ji7 ,pl4 iii4 #abac ,krasser 7#ab74 #abad ,lignier 7#jc74 #abae ,wieland 7#jf7 p4 #aeb4 #abaf ,lignier 7#jg72 ,wieland 7#aa7 p4 #dfb4 #abag ,nathorst 7#aa7 ,pl4 ii4 #abah ,thomas 7#ae74 #abai ,thomas 7#ae74 #abbj ,nathorst 7#ji7 p4 #f1 ,pls4 i41 ii42 7#aa7 p4 #e1 ,pls4 i41 iii42 7#ab74 #abba ,thomas 7#ac7 p4 #bcj1 ,pl4 xxiv4 figs4 #a-c4 #abbb ,capellini and ,solms-,laubach 7#ib7 ,pl4 v4 fig4 #g4 #abbc ,nathorst 7#ji7 ,pl4 i4 figs4 #a-c4 #abbd ,ibid4 7#hj7 p4 #ci4 ,see also ,saporta 7#ia7 p4 #afa1 ,pl4 #bdh4 #abbe ,seward 7#jj7 ,b4 p4 #bja1 fig4 #ce4 #abbf ,nathorst 7#ji7 p4 #ad1 ,pls4 ii41 iii4 #abbg ,carruthers 7#gj7 p4 #fid4 #abbh ,nathorst 7#aa7 p4 #ai4 #abbi ,nathorst 7#aa7 p4 #i1 ,pls4 ii41 iii4 ,see also ,nathorst 7#ji7 p4 #h1 ,pls4 i41 ii4 #abcj ,leckenby 7#fd7 ,a4 #abca ,nathorst 7#ab7 p4 #g4 #abcb ,williamson 7#gj7 ,pl4 lii4 fig4 #a2 ,pl4 liii4 fig4 #b4 #abcc ,seward 7#jj7 ,b4 p4 #bja1 ,pl4 ii4 fig4 #g4 #abcd ,nathorst 7#aa7 p4 #ai1 ,pl4 v4 figs4 #a-h2 ,pl4 vi4 figs4 #a-c4 ,the name ,palaeozamia pecten was applied by ,leckenby ,leckenby 7#fd7 ,a4 p4 #gg1 ,pl4 ix4 fig4 #dg both to the fronds and an associated flower which is now recognised as a whorl of microsporophylls4 ,i formerly employed the name ,williamsonia pecten for fronds and flowers1 but in view of ,nathorst's work it is advisable to follow his example and to use separate names for male and female flowers when there is no proof that they belong to one type2 similarly the fronds may conveniently be spoken of as ,ptilophyllum pecten4 #abce ,nathorst 7#aa7 p4 #ag1 ,pl4 iv4 #abcf ,nathorst 7#ji7 ,pl4 vii4 fig4 #a4 #abcg ,see page #ddd4 #abch ,oldham and ,morris 7#fc7 ,b4 ,pl4 xxxii4 fig4 #b4 #abci ,feistmantel 7#gg7 p4 #gf2 7#gg7 ,pl4 ii4 fig4 #e4 #abdj ,ibid4 7#gg7 ,pl4 xliv4 fig4 #b4 #abda ,feistmantel 7#gg7 ,pl4 xliv4 figs4 #c1 #d4 #abdb ,williamson 7#gj7 ,pl4 lii4 fig4 #a4 #abdc ,wieland 7#aa7 p4 #dfj1 fig4 #af ,b4 #abdd ,nathorst 7#ji7 p4 #f4 #abde ,feistmantel 7#gg7 ,pl4 xli4 fig4 #d2 7#gg7 ,pl4 i4 fig4 #f2 ,pl4 ii4 fig4 #d4 #abdf ,ibid4 7#gf7 p4 #eb1 ,pl4 xii4 figs4 #e-g2 7#gg7 ,pl4 i4 figs4 #d1 #e2 ,pl4 ii4 fig4 #f4 #abdg ,feistmantel 7#gg7 p4 #aha1 ,pl4 vii4 figs4 #a-d2 7#gg7 ,pl4 ii4 figs4 #a-c4 #abdh ,my thanks are due to ,mr ,wieland for a photograph of this species that is mentioned but not figured in his paper on the ,mexican ,flora1 ,wieland 7#ac74 #abdi ,bancroft 7#ac7 p4 #gf1 ,pl4 vii4 figs4 #a-e4 #abej ,seward 7#ie7 ,a4 p4 #aeg1 ,pls4 x41 xi4 #abea ,buckland 7#cg7 ,vol4 i4 p4 #eje1 ,vol4 ii4 p4 #aja1 ,pl4 lxiii4 figs4 #b-aj4 #abeb ,unger 7#ej7 ,a4 p4 #cbg4 #abec ,brongniart 7#di7 ,a4 p4 #hh4 #abed ,saporta 7#ia7 p4 #abg1 ,pls4 #bch1 #bci4 #abee ,for other references1 see ,seward 7#jd7 ,b4 p4 #aje4 #abef ,miller 7#eg7 ,b4 p4 #dhj4 ,for a detailed description and illustrations1 see ,seward 7#ab74 #abeg ,thomas and ,bancroft 7#ac7 p4 #ahd4 #abeh ,bancroft 7#ac74 #abei ,lignier 7#ja74 #abfj ,nathorst 7#aa7 p4 #bd1 ,pl4 v4 figs4 #i-aa4 #abfa ,wieland 7#aa7 p4 #dfb4 #abfb ,nathorst 7#ji7 p4 #aj2 7#aa7 p4 #ad4 #abfc ,nathorst 7#ji7 p4 #aj4 #abfd ,williamson 7#gj7 ,pl4 lii43 see also ,seward 7#jj7 ,b1 ,pl4 viii4 fig4 #a4 #abfe ,nathorst 7#ji7 p4 #ab1 fig4 #b4 #abff ,lignier 7#jc7 p4 #cd4 #abfg ,in addition to the papers already quoted1 reference should also be made to ,thomas 7#ae74 #abfh ,wieland 7#ji7 p4 #dcj 7the species is here referred to as the #8,el consuelo ,williamsonia'72 7#aa7 p4 #dfa1 fig4 #ag ,c4 #abfi ,zigno 7#he7 ,pl4 xlii4 #abgj ,seward 7#ab7 p4 #bf1 ,pl4 iii4 fig4 #dd2 ,pl4 vii4 fig4 #hf4 #abga ,zigno 7#he7 p4 #agc1 ,pl4 xlii4 figs4 #i-aa4 #abgb ,seward 7#aa7 p4 #fia1 ,pl4 v4 fig4 #ii4 #abgc ,fontaine in ,ward 7#je7 ,b4 p4 #aah1 ,pl4 xxix4 fig4 #f4 #abgd ,nathorst 7#hj7 p4 #da1 ,pl4 viii4 fig4 #g4 #abge ,saporta 7#id7 ,b4 p4 #aje1 ,pl4 xix4 fig4 #i4 #abgf ,newberry and ,hollick 7#ie7 p4 #abe1 ,pl4 xxxv4 figs4 #a-i4 #abgg ,hollick 7#jf7 p4 #ajg1 ,pl4 v4 figs4 #bg-cb2 7#ab7 p4 #aef1 ,pl4 clxiii4 fig4 #d4 #abgh ,newberry and ,hollick 7#ie7 p4 #abg1 ,pl4 xxxvi4 figs4 #a-h4 #abgi ,hollick 7#jf7 p4 #ajg1 ,pl4 v4 figs4 #be1 #bf4 #abhj ,ward 7#ii7 ,b4 p4 #ffh1 ,pl4 clxii4 fig4 #bj4 #abha ,lesquereux 7#ia7 p4 #hg1 ,pl4 ii4 fig4 #i4 #abhb ,fontaine 7#hi7 ,b4 p4 #bgc1 ,pls4 #acc1 #afe4 #abhc ,fontaine in ,ward 7#je7 ,b4 p4 #dhe1 ,pl4 cvii4 fig4 #d4 #abhd ,ward 7#je7 ,b4 p4 #eed1 ,pl4 cxv4 fig4 #aa4 #abhe ,berry 7#aa7 p4 #dje1 ,pl4 lxvii4 figs4 #a-d4 #abhf ,heer 7#hb7 ,b1 p4 #ei1 ,pls4 xii41 xiii4 #abhg ,dawson 7#he7 p4 #ab1 ,pl4 iv4 fig4 #a4 #abhh ,nathorst 7#hj7 p4 #ej4 #abhi ,ibid4 7#hh72 7#jb7 p4 #i1 ,pls4 i4-iii4 #abij ,ibid4 7#ji7 p4 #bb1 ,pls4 v41 vi4 #abia ,ibid4 p4 #cc4 #abib ,south and ,compton 7#jh7 p4 #bbe1 fig4 #cf4 #abic ,for figures of the stem and flowers1 see ,nathorst 7#jb72 7#ji74 #abid ,thomas 7#ae74 #abie ,nathorst retains the name ,anomozamites minor for the leaves1 restricting ,wielandiella to the plant as a whole including strobili and stems which usually occur in organic union ,nathorst 7#ac74 #abif ,nathorst 7#ji7 p4 #be1 ,pl4 vii4 figs4 #ad-bb4 #abig ,thomas 7#ac71 p4 #bci4 #abih ,nathorst 7#jb7 p4 #af4 #abii ,thiselton-,dyer 7#gb74 #acjj ,wieland 7#aa7 p4 #deh4 #acja ,thomas 7#ae74 #acjb ,see page #ddi4 #acjc ,see page #dfc4 #acjd ,seward 7#jj7 ,b4 xvi4 fig4 #a2 ,thomas1 ,h4 ,h4 7#ae7 ,pl4 xiv4 fig4 #bf4 #acje ,nathorst 7#jb7 p4 #g1 ,pl4 #a4 #acjf ,ibid4 7#ji7 p4 #bg1 ,pl4 viii42 7#ab7 ,pls4 i41 ii42 7#ab74 #acjg ,see the photographs reproduced in ,nathorst's latest and most complete account 7#ab74 #acjh ,bower 7#ig7 ,b4 #acji ,braun 7#di74 7,i have not seen this paper47 #acaj ,saporta 7#ia7 p4 #aia1 ,pls4 #bec-bee4 #acaa ,see page #dbh4 #acab ,nathorst 7#ji7 p4 #bh4 #acac ,ibid4 7#aa72 7#ab74 #acad ,schuster 7#aa74 #acae ,schimper 7#gb7 ,a4 p4 #bjj4 #acaf ,zeitsch4 f4 ,bot4 #aiab1 p4 #def4 #acag ,saporta 7#ia7 pp4 #bjd1 #bjf1 ,pls4 #bed1 #bee4 #acah ,mantell 7#bg74 #acai ,see page #dfc4 #acbj ,carruthers 7#gj74 #acba ,saporta 7#ge7 ,a4 pp4 #bef et seq4 #acbb ,saporta 7#ge7 ,a4 p4 #bic1 ,pls4 #abc1 #abd4 #acbc ,see p4 #dae4 #acbd ,saporta 7#ge7 ,a4 p4 #bef4 #acbe ,presl in ,sternberg 7#be7 ,a4 p4 xxxiii4 #acbf ,mantell 7#bg74 #acbg ,stokes and ,webb 7#bd74 #acbh ,brongniart 7#bb7 ,a4 p4 #bji2 7#bh7 ,a4 p4 #abh4 #acbi ,carruthers 7#gj7 p4 #fhb4 #accj ,carruthers 7#fg72 7#gj7 p4 #fhh4 #acca ,stopes 7#ae7 p4 #cji4 ,see postea1 p4 #dhf4 #accb ,nathorst 7#hf7 ,pl4 xviii4 fig4 #e4 #accc ,stokes and ,webb 7#bd7 ,pls4 xiv4-xvii4 #accd ,carruthers 7#gj7 p4 #fhf1 ,pl4 liv4 ,see also ,seward 7#ie7 ,a4 p4 #abc4 #acce ,seward 7#ie7 ,a4 p4 #acb1 ,pl4 ix4 fig4 #f2 7#ac7 p4 #aja4 #accf ,ibid4 ,pl4 i4 fig4 #b4 #accg ,carruthers 7#gj7 p4 #fhi1 ,pl4 lv4 fig4 #b4 #acch ,seward 7#jd7 ,b4 p4 #de4 #acci ,carruthers 7#gj7 p4 #fhg1 ,pl4 lv4 fig4 #a4 #acdj ,carruthers1 p4 #fhi1 ,pl4 lv4 figs4 #g-i4 #acda ,carruthers 7#fg72 7#gj7 p4 #fhh1 ,pl4 lv4 figs4 #c-f4 ,see also ,seward 7#ie7 ,a4 p4 #aff4 #acdb ,stopes 7#ae7 p4 #bii1 text-figs4 #ic-ig4 #acdc ,stopes 7#ae7 p4 #cji1 text-figs4 #ih-ajj4 #acdd ,sternberg 7#be7 ,a4 ,pl4 #cj4 #acde ,brongniart 7#bh7 ,a4 p4 #abh4 #acdf ,carruthers 7#gj7 p4 #fhf4 #acdg ,ibid4 7#gj7 p4 #fij1 ,pl4 lvi4 #acdh ,saporta 7#ge7 ,a4 p4 #cjh1 ,pls4 #abe1 #abf4 #acdi ,ibid4 p4 #cbb1 ,pl4 #abg1 figs4 #a-c4 #acej ,oldham and ,morris 7#fc7 ,b4 ,pl4 xxxiv4 #acea ,feistmantel 7#gg7 p4 #gh4 #aceb ,wieland 7#aa7 p4 #ddj4 #acec ,seward 7#jj7 ,b4 p4 #aid4 #aced ,bancroft 7#ac74 #acee ,for illustrations and further details see ,bancroft 7#ac74 #acef ,saporta 7#ge7 ,a4 p4 #cca1 ,pl4 #aai1 fig4 #c4 #aceg ,lignier 7#ie7 p4 #aa1 fig4 #a4 #aceh ,ibid4 p4 #ae1 fig4 #b4 #acei ,stokes and ,webb 7#bd7 ,pl4 xlv42 ,mantell 7#bg71 etc4 ,see ,seward 7#ie7 ,a4 pp4 #abf1 #acj1 etc41 for other references4 #acfj ,ward 7#ii7 ,b4 p4 #fic1 ,pl4 #afi1 fig4 #ai4 #acfa ,feistmantel 7#gf7 ,pl4 x4 fig4 #b4 #acfb ,hollick and ,jeffrey 7#ji7 ,b4 p4 #ag4 #acfc ,stopes 7#ae7 p4 #cad1 ,pls4 xxxi41 xxxii41 text-figs4 #aja-aaa4 #acfd ,saporta 7#ge7 ,a4 p4 #bjj1 ,pl4 #aad1 figs4 #d-f4 #acfe ,seward 7#ie7 ,a4 p4 #if4 #acff ,feistmantel 7#gf7 ,pl4 vii4 fig4 #e4 #acfg ,seward 7#ie7 ,a4 p4 #ih1 ,pl4 v4 figs4 #b1 #f2 7#jc7 ,b4 p4 #ca4 #acfh ,ibid4 7#ac7 p4 #aja1 ,pl4 xii4 figs4 #c1 #d2 ,pl4 xiv4 fig4 #f4 #acfi ,saporta 7#ge7 ,a4 ,pl4 #abg4 #acgj ,carruthers 7#gj7 ,pl4 lvi4 #acga ,i am indebted to ,mr ,edwards of the ,geological ,department of the ,british ,museum for making a preparation of the cuticle4 #acgb ,tate 7#fg7 ,pl4 vi4 fig4 #d2 ,seward 7#jc7 ,b4 p4 #bi1 ,pl4 iv4 figs4 #c-f4 #acgc ,for further reference to this generic name1 as applied to ,palaeozoic seeds1 see page #cfd4 #acgd ,nathorst 7#ad7 p4 #cc4 #acge ,ward 7#jj7 ,b4 p4 #cfc4 #acgf ,pomel 7#di7 p4 #af4 #acgg ,lindley and ,hutton 7#cf7 ,a4 ,pl4 #ahi4 ,see also ,seward 7#jd7 ,b4 p4 #abd4 #acgh ,lindley and ,hutton 7#cf7 ,a4 ,pl4 #ahi1 figs4 #c1 #e4 #acgi ,seward 7#ie7 ,a4 p4 #aje1 fig4 #g4 #achj ,saporta 7#ge7 ,a4 p4 #bdb1 ,pl4 #aag1 fig4 #i4 #acha ,fontaine 7#hi7 ,b4 p4 #bgj1 ,pls4 #ace1 #acf4 #achb ,compter1 ,g4 7#jc74 #achc ,schimper 7#gb7 ,a4 p4 #bjg1 ,pl4 lxxii4 figs4 #ah-bc4 #achd ,pomel 7#di7 p4 #ac4 #ache ,schenk 7#fg7 ,a4 p4 #aej1 ,pl4 xxxiii4 fig4 #aj4 #achf ,see page #ada4 #achg ,zigno 7#he7 p4 #aef1 ,pl4 xlii4 #achh ,saporta 7#ia7 p4 #dff1 ,pl4 #bih4 #achi ,seward 7#aa7 p4 #fii1 ,pl4 vii4 fig4 #ah4 #acij ,saporta 7#ge7 ,a4 ,pl4 #aaf2 7#ia7 ,pl4 #bih4 #acia ,saporta and ,marion 7#he7 p4 #aaa4 #acib ,nathorst 7#hf7 p4 #hj1 ,pl4 xvii4 fig4 #g4 #acic ,ibid4 7#jb7 p4 #f1 ,pl4 i4 fig4 #aa4 #acid ,carruthers 7#fi74 #acie ,lindley and ,hutton 7#ce7 ,a4 ,pl4 #aei4 #acif ,seward and ,gowan 7#jj7 ,b4 p4 #adc2 ,seward 7#jj7 ,b4 p4 #bge1 ,pl4 ix4 fig4 #aa4 #acig ,nathorst 7#jb7 p4 #ba1 ,pl4 i4 figs4 #ad1 #ae4 #acih ,nathorst 7#jb7 p4 #bj1 ,pl4 i4 figs4 #bb1 #bc4 #acii ,ibid4 7#ji7 p4 #bc4 #adjj ,see ,vol4 iv4 #adja ,endlicher 7#dj7 p4 #gb4 ,see also ,schimper 7#gb7 ,a4 p4 #bja4 #adjb ,lindley and ,hutton 7#ce7 ,a4 ,pl4 #abe4 #adjc ,carruthers 7#fg7 p4 #ajd4 #adjd ,heer 7#gg7 ii4 p4 #dg1 ,pl4 xiii4 fig4 #aj4 #adje ,fliche 7#if7 p4 #bg1 ,pl4 i4 fig4 #c4 #adjf ,seward 7#ie7 ,a4 pp4 #aac et seq42 7#if7 ,a4 p4 #bae2 7#jd7 ,b4 pp4 #ach1 #aej4 #adjg ,solms-,laubach 7#ia7 ,a4 p4 #ib4 #adjh ,lindley and ,hutton 7#ce7 ,a4 ,pl4 #acf4 #adji ,corda in ,reuss 7#df7 ,b4 ,pl4 xlvi4 #adaj ,velenovsk 7#he7 ,b4 ,pl4 #f1 ,pls4 iii4-v4 #adaa ,carruthers 7#gj7 ,pl4 liv4 fig4 #f4 #adab ,saporta and ,marion 7#he7 p4 #aaf1 fig4 #fa1 ,b4 #adac ,schimper 7#gb7 ,a4 p4 #aii4 #adad ,see ,vol4 iv4 #adae ,saporta 7#ge7 ,a4 p4 #bji1 ,pl4 #aae1 figs4 #a1 #b4 #adaf ,heer 7#gg7 ii4 p4 #dg1 ,pl4 iv4 figs4 #ad1 #ae4 #adag ,nathorst 7#gh7 ,b4 p4 #di1 ,pl4 ii4 figs4 #ae1 #af4 #adah ,corda in ,reuss 7#df7 ,b4 p4 #hf1 ,pl4 xlix4 figs4 #aj1 #aa4 #adai ,carruthers 7#fg7 p4 #f4 #adbj ,velenovsk 7#he7 ,b4 p4 #h1 ,pl4 iii4 figs4 #a-c1 #f1 #aa4 #adba ,vol4 ii4 p4 #hh4 #adbb ,seward 7#ie7 ,a4 p4 #aaj1 ,pl4 ix4 figs4 #a-d4 #adbc ,i am indebted to ,mr ,w4 ,n4 ,edwards of the ,british ,museum for the cuticular preparations4 #adbd ,newberry 7#hh7 p4 #cdf1 ,pl4 viii4 fig4 #e4 #adbe ,lesquereux 7#ia7 p4 #bi1 ,pl4 i4 fig4 #ab4 #adbf ,fontaine 7#hi7 ,b4 p4 #agd1 ,pl4 lxx4 fig4 #d2 ,pl4 lxxi4 figs4 #c1 #d1 etc4 #adbg ,saporta 7#gd72 ,saporta and ,marion 7#he7 p4 #aaf1 fig4 #fa ,c4 #adbh ,ettingshausen 7#hh7 p4 #bgb1 ,pl4 iii4 fig4 #aj4 #adbi ,thomas1 ,h4 ,h4 7#ae74 #adcj ,gutbier 7#di7 ,pl4 viii4 fig4 #g4 ,for a fuller account of ,palaeozoic records1 see ,seward 7#ie7 ,a4 p4 #i4 #adca ,eichwald 7#ee7 ,vol4 i4 ,pl4 xv4 figs4 #e1 #f2 ,zeiller 7#if7 ,a4 p4 #dgd4 #adcb ,sandberger 7#fd7 ,pl4 ii4 figs4 #a-d4 #adcc ,saporta and ,marion 7#he7 p4 #aji2 ,zeiller 7#jf7 ,b4 p4 #aid4 #adcd ,goeppert 7#dd7 ,pl4 i4 fig4 #f4 #adce ,ibid4 7#ff7 ,pl4 ii4 #adcf ,saporta and ,marion 7#gh7 ,pl4 i4 figs4 #d1 #e4 #adcg ,ibid4 7#he7 fig4 #fa1 ,a1 p4 #aaf4 #adch ,krasser 7#jc7 p4 #heb4 #adci ,ettingshausen 7#hf7 ,pl4 viii4 figs4 #ai-ba2 7#hh7 ,pl4 viii4 figs4 #ai-ba4 #addj ,nathorst 7#ab7 p4 #cf4 #adda ,thomas and ,bancroft 7#ac74 #addb ,the genus ,ptilozamites described briefly in ,volume ii4 has recently been fully investigated by ,antevs#addc who had access to the rich material in the ,stockholm ,museum from the ,rhaetic beds of ,scania4 ,he thinks that the genus is intermediate between ,anomozamites and ,ctenopteris2 its systematic position has not been definitely established but1 as ,antevs says1 there seems to be no reason why it should not be a member of the ,cycadophyta4 ,in some species1 e4g4 ,ptilozamites fallax ,nath4 and ,p4 ,nilssoni ,nath41 the rachis is forked1 while in ,p4 ,heeri ,nath4 with linear fronds reaching a length of #ec cm4 the rachis is undivided4 #addc ,antevs 7#ad74 #addd ,see page #ejb4 #adde ,nathorst 7#jh7 ,pl4 i4 figs4 #c-e2 ,thomas and ,bancroft 7#ac7 p4 #aid1 ,pl4 xx4 fig4 #ab4 #addf ,fontaine 7#hi7 ,b4 p4 #afj1 ,pls4 lxi4-lxvi42 ,berry 7#aa7 p4 #ced4 #addg ,morris 7#dj7 ,pl4 xxi4 figs4 #a-d4 #addh ,lindley and ,hutton 7#cd7 ,a4 ,pl4 cii4 #addi ,morris 7#da7 p4 #aaf4 #adej ,ibid4 7#ed7 p4 #ae4 #adea ,oldham and ,morris 7#fc7 ,b4 p4 #bg4 #adeb ,feistmantel 7#gf74 #adec ,ibid4 7#gf7 p4 #db4 #aded ,ibid4 7#gg7 ,pl4 xl4 figs4 #a1 #b4 #adee ,ibid4 7#gg7 p4 #id1 ,pls4 v4 vi4 #adef ,ibid4 7#gi74 #adeg ,ibid4 7#gg74 #adeh ,seward 7#jj7 ,b4 p4 #aic4 #adei ,ibid4 7#jc7 p4 #bbg4 #adfj ,halle 7#ac74 #adfa ,halle 7#ac74 #adfb ,thomas and ,bancroft 7#ac7 p4 #ahd4 #adfc ,phillips 7#bi7 ,a4 ,pl4 vii4 fig4 #bb2 ,pl4 x4 fig4 #d4 #adfd ,heer 7#ge7 ii4 #adfe ,halle 7#ac74 #adff ,ibid4 #adfg ,heer 7#ge7 ii4 ,pls4 xiv4-xvi4 #adfh ,phillips 7#bi7 ,a4 ,pl4 vii4 fig4 #bb2 ,pl4 x4 fig4 #d4 #adfi ,sternberg 7#bc7 ,a4 ,pl4 xxxiii4 fig4 #a4 ,for other references1 see ,seward 7#jj7 ,b4 p4 #aij2 7#jd7 ,b4 p4 #ajf4 #adgj ,brongniart 7#bh7 ,a4 p4 #id4 #adga ,lindley and ,hutton 7#ce7 ,a4 ,pl4 #agb4 #adgb ,brongniart 7#bh7 ,a4 p4 #id4 #adgc ,andrae 7#ec7 ,a4 ,pl4 xi4 fig4 #a4 #adgd ,seward 7#jg7 p4 #bi4 #adge ,nathorst 7#jd7 ,b2 ,halle 7#ac74 #adgf ,halle 7#ac74 #adgg ,heer 7#ge7 ii4 p4 #ff1 ,pls4 xiv41 xv4 #adgh ,halle 7#ac7 p4 #eh1 ,pl4 vii4 #adgi ,ibid4 p4 #ef1 ,pl4 vii4 #adhj ,goeppert 7#dd7 p4 #eb4 #adha ,dunker 7#df7 ,a4 p4 #ad1 ,pl4 ii4 fig4 #c2 ,pl4 vi4 fig4 #d4 #adhb ,miquel 7#ea7 p4 #bab4 #adhc ,seward 7#ie7 ,a4 p4 #ch4 #adhd ,schimper 7#gj7 ,a4 p4 #abg4 #adhe ,schenk 7#ga7 ,b4 ,pl4 xxxvi4 #adhf ,brongniart 7#bh7 ,a4 p4 #id4 #adhg ,schenk 7#ga7 ,b4 p4 #h4 #adhh ,schenk 7#fg7 ,a4 ,pls4 xxxvi4--vii4 #adhi ,goeppert 7#dd7 p4 #abb4 #adij ,pomel 7#dg7 p4 #cdb4 #adia ,bornemann 7#ef7 ,a4 p4 #ed4 #adib ,nathorst 7#ij7 ,a4 p4 #df4 #adic ,seward 7#ie7 ,a4 p4 #ge4 #adid ,zeiller 7#jc7 ,b4 p4 #afe4 #adie ,halle 7#ac7 p4 #ee4 #adif ,schimper 7#gb7 ,a4 pp4 #abh1 #afc4 #adig ,kurr1 ,j4 ,g4 7#de7 ,b4 ,pl4 i4 fig4 #e4 #adih ,schenk 7#ga7 ,b4 p4 #h1 ,pl4 i4 fig4 #h4 #adii ,saporta 7#id7 ,b4 ,pl4 xvi4 #aejj ,yokoyama 7#id7 ,pl4 xxi4 fig4 #e4 #aeja ,feistmantel 7#gi7 p4 #ah4 ,this statement is based on an examination of the specimen4 #aejb ,zeiller 7#id7 ,b4 p4 #agd4 #aejc ,halle 7#ac7 p4 #ee4 #aejd ,see page #ebe4 #aeje ,thomas and ,bancroft 7#ac7 p4 #ahd4 #aejf ,zeiller 7#jc7 ,b4 p4 #aff1 ,pl4 xliii4 figs4 #c-f4 #aejg ,brongniart 7#bh7 ,a4 p4 #id4 ,see ,seward 7#jj7 ,b4 p4 #agh4 #aejh ,lindley and ,hutton 7#ch7 ,a4 ,pl4 clxv4 #aeji ,saporta 7#ge7 ,a4 ,pls4 ,,lxxxvii-,,xcii4 #aeaj ,ibid4 ,pls4 lxxxiv41 lxxxv4 #aeaa ,ibid4 ,pl4 xciii4 #aeab ,saporta 7#ge7 ,a4 ,pl4 xciii4 #aeac ,andrae 7#ec7 ,a4 ,pl4 ix4 #aead ,fri and ,bayer 7#ja7 ,b4 fig4 #dc1 p4 #ib4 #aeae ,hosius and von der ,march 7#hj7 ,b4 ,pl4 xliv4 fig4 #bjb4 #aeaf ,tate 7#fg7 ,pl4 v4 fig4 #g4 #aeag ,seward 7#jc7 ,b4 p4 #ba1 ,pls4 iii4 v4 #aeah ,no4 #aaaag4 #aeai ,seward 7#ie7 ,a4 p4 #hf1 ,pl4 vi4 #aebj ,ibid4 7#aa7 p4 #fid1 ,pl4 x4 fig4 #dc4 #aeba ,miller 7#eg7 ,b4 fig4 #acf4 #aebb ,richards 7#hd7 p4 #abj4 #aebc ,ettingshausen 7#eb7 ,b4 p4 #ba1 ,pl4 i4 fig4 #a2 ,seward 7#ie7 ,a4 p4 #gi1 ,pls4 iii41 iv41 viii4 #aebd ,goeppert 7#dg7 ,pl4 xxxviii4 #aebe ,fontaine 7#hi7 ,b4 p4 #ahb1 ,pls4 lxviii4-lxxiv41 etc4 #aebf ,yokoyama 7#id7 p4 #bbc1 ,pls4 xx41 xxiii41 etc4 #aebg ,nathorst 7#ij7 ,a4 ,pls4 ii41 iii41 v4 #aebh ,braun in ,mnster 7#db7 ,b4 p4 #cf4 #aebi ,seward 7#ie7 ,a4 p4 #ef4 #aecj ,heer 7#ge7 ii4 ,pl4 xxvi4 fig4 #b2 the specimen is in the ,stockholm ,museum4 #aeca ,halle 7#ac7 p4 #ee4 #aecb ,zigno 7#he7 ,pl4 xlii4 fig4 #i4 #aecc ,wieland 7#ac74 #aecd ,schenk 7#fg7 ,a4 ,pl4 xxxiv4 fig4 #g4 #aece ,thomas and ,bancroft 7#ac7 p4 #ahf1 ,pl4 xix4 figs4 #c1 #d4 #aecf ,seward 7#ie7 ,a4 ,pl4 i4 figs4 #a1 #b4 #aecg ,brongniart 7#be7 ,pl4 xix4 fig4 #d2 ,seward 7#jj7 ,b4 p4 #bai2 7#jd7 ,b4 p4 #ci4 #aech ,lindley and ,hutton 7#cd7 ,a4 ,pl4 cxxviii4 #aeci ,zeiller 7#ab7 p4 #f2 ,halle 7#ac7 p4 #fc 7footnote74 #aedj ,seward 7#jj7 ,b4 p4 #bah4 #aeda ,leckenby 7#fd7 ,a4 ,pl4 viii4 fig4 #e2 ,seward 7#jj7 ,b4 p4 #bac1 ,pls4 i41 ii4 #aedb ,zigno 7#ha7 ,pl4 xxxiii4 figs4 #c1 #d4 #aedc ,saporta 7#ge7 ,a4 ,,pl4 #aja4 #aedd ,ibid4 ,pl4 #ii4 #aede ,halle 7#ac7 ,pl4 vii4 #aedf ,heer 7#ge7 ii4 ,pl4 xvi4 figs4 #e-h4 #aedg ,schenk 7#fg7 ,a4 ,pls4 xxxiii41 xxxiv4 #aedh ,zeiller 7#jc7 ,b4 ,pl4 xliii4 fig4 #a4 #aedi ,krasser 7#ia7 p4 #ab4 #aeej ,zeiller 7#je74 #aeea ,lindley and ,hutton 7#cb7 ,a4 ,pl4 xliv4 #aeeb ,leckenby 7#fd7 ,a4 ,pl4 x4 fig4 #b4 #aeec ,zigno 7#he7 ,pls4 xxxv4-xxxvi4 #aeed ,zigno 7#ec7 p4 #aa2 ,seward 7#jj7 ,b4 p4 #baa4 #aeee ,leckenby 7#fd7 ,a4 ,pl4 ix4 fig4 #c4 #aeef ,feistmantel 7#gi7 ,pls4 vii41 xvi4 #aeeg ,mller 7#jc7 ,pl4 i4 #aeeh ,zigno 7#ha7 ,pl4 xxiv42 ,thomas and ,bancroft 7#ac7 p4 #ahf2 ,seward 7#jj7 ,b4 p4 #bba4 #aeei ,oldham and ,morris 7#fc7 ,b4 p4 #bg1 ,pl4 xix42 ,feistmantel 7#gf7 ,pl4 vii4 fig4 #d4 #aefj ,dunker 7#df7 ,a4 p4 #aa1 ,pl4 ix4 figs4 #f1 #g2 ,seward 7#ie7 ,a4 p4 #fj4 #aefa ,saporta 7#ge7 ,a4 ,pls4 cx41 cxi4 #aefb ,ibid4 ,pl4 cx4 #aefc ,thomas 7#aa7 p4 #hc1 ,pls4 v41 vi4 #aefd ,fontaine in ,ward 7#je7 ,b4 ,pl4 xxxviii4 #aefe ,nathorst 7#ac7 p4 #bgi4 #aeff ,dunker 7#df7 ,a4 p4 #ad1 ,pl4 ii4 fig4 #e2 ,seward 7#ie7 ,a4 p4 #gj1 ,pl4 i4 #aefg ,oldham and ,morris 7#fc7 ,b4 p4 #cg4 #aefh ,seward 7#jc74 #aefi ,yabe 7#je7 ,b4 ,pl4 ii4 figs4 #b-g4 #aegj ,halle 7#ab72 7#ac7 p4 #i1 ,pl4 v4 figs4 #bi-cc4 #aega ,bancroft 7#ac74 #aegb ,oldham and ,morris 7#fc7 ,b4 ,pl4 xxiv4 figs4 #a1 #b2 ,feistmantel 7#gf7 ,pls4 iv4-vi42 7#gg7 ,pl4 ii4 #aegc ,yokoyama 7#hi7 ,b1 ,pl4 vii4 fig4 #aj2 ,pls4 x41 xi4 #aegd ,seward 7#jc7 p4 #bag4 #aege ,the statement made by me ,seward 7#aa7 p4 #c that ,dictyozamites occurs in the ,falklands is incorrect4 #aegf ,nathorst 7#hi72 ,mller 7#jc7 p4 #be1 ,pl4 v4 #aegg ,nathorst 7#jg7 ,pl4 iii4 figs4 #b-h4 #aegh ,seward 7#jc72 ,thomas 7#ac7 p4 #bch2 ,thomas and ,bancroft 7#ac7 p4 #ahf1 ,pl4 xix4 figs4 #f-h4 #aegi ,brongniart 7#be74 #aehj ,nathorst 7#ha7 p4 #fa4 #aeha ,brongniart 7#bh7 ,a4 p4 #ie4 #aehb ,heer 7#ge7 ii4 ,pl4 xv4 fig4 #aa4 #aehc ,schimper 7#gb7 ,a4 p4 #adj4 #aehd ,potoni 7#ii7 ,b4 p4 #bha4 #aehe ,zeiller 7#jc7 ,b4 p4 #agd4 #aehf ,halle 7#ae7 p4 #eae1 ,pl4 xiii4 figs4 #ah-bj1 #bb4 #aehg ,heer 7#gf7 ,a4 ,pl4 xxxv4 fig4 #c4 #aehh ,leuthardt 7#jc7 p4 #bj4 #aehi ,see page #dfc4 #aeij ,thomas 7#ac7 p4 #bcg4 #aeia ,schenk 7#fg7 ,a4 ,pls4 xxxvii4-viii4 #aeib ,ibid4 ,pl4 xxxix4 fig4 #g4 #aeic ,thomas and ,bancroft 7#ac7 ,pl4 xix4 fig4 #e4 #aeid ,ettingshausen 7#hf7 ,pl4 viii4 figs4 #ai-ba4 #aeie ,renault and ,zeiller 7#hh7 ,a4 p4 #fai1 ,pl4 lxviii4 #aeif ,arber1 ,e4 ,a4 ,n4 7#ab74 #aeig ,sandberger 7#fd7 ,pl4 ii4 figs4 #a-d4 #aeih ,renault 7#if7 ,a4 p4 #cbb1 fig4 #fd4 #aeii ,saporta and ,marion 7#he7 p4 #aji1 fig4 #eh ,a4 #afjj ,sandberger 7#fd7 ,pl4 ii4 figs4 #a-d4 #afja ,geinitz 7#gc7 ,pl4 iii4 fig4 #i4 #afjb ,geinitz fig4 #h4 #afjc ,brongniart 7#bh7 p4 #ie4 #afjd ,leuthardt 7#jc7 p4 #ad1 ,pl4 v4 #afje ,ibid4 p4 #af1 ,pl4 v4 #afjf ,ibid4 ,pl4 vii4 fig4 #d2 ,pl4 viii4 figs4 #c-e4 #afjg ,krasser 7#ji74 #afjh ,schenk 7#fg7 ,pl4 ii4 ,there are some fine examples from the ,raibl beds in the ,vienna ,geological ,survey ,collection4 #afji ,arber 7#jg74 #afaj ,fontaine 7#hc7 ,b4 p4 #hj1 ,pls4 xliii4-v4 #afaa ,schimper 7#gb7 ,a4 pp4 #abg1 #acb4 #afab ,schenk 7#fg7 ,pl4 ii4 #afac ,goeppert 7#dd72 ,schenk 7#fg7 ,a4 p4 #afd1 ,pl4 xxxviii4 #afad ,schenk 7#hg7 ,b4 p4 #f1 ,pls4 vi41 ix4 #afae ,zeiller 7#jc7 ,b4 p4 #ahi1 ,pl4 xlvii4 fig4 #a4 #afaf ,zeiller 7#jc7 ,b4 p4 #aih1 ,pl4 xlix4 figs4 #a-c4 #afag ,ibid4 7#je7 p4 #aid4 #afah ,braun1 ,f4 7#dc74 #afai ,zeiller 7#jc7 ,b4 p4 #agg1 ,pl4 xliii4 fig4 #h2 ,pl4 xliv4 figs4 #a-e4 #afbj ,schenk 7#fg7 ,a4 ,pl4 xxxviii4 figs4 #e-i4 #afba ,zeiller 7#jc7 ,b4 ,pl4 xliii4 fig4 #g4 #afbb ,feistmantel 7#hf7 ,pl4 ii4 ,a4 figs4 #d-h4 #afbc ,seward 7#jj7 ,b4 p4 #bci4 #afbd ,seward 7#aa7 p4 #fid1 ,pls4 iv41 v4 etc4 #afbe ,zeiller 7#jc7 ,b4 ,pl4 xix4 #afbf ,fontaine in ,ward 7#je7 ,b4 ,pl4 xxii4 #afbg ,schenk 7#ga7 ,b4 ,pl4 xxiv4 fig4 #e4 #afbh ,oldham and ,morris 7#fc7 ,b4 ,pl4 ix42 ,feistmantel 7#gg7 ,pls4 v41 vi4 #afbi ,phillips 7#bi7 ,a4 ,pl4 viii4 fig4 #d4 #afcj ,see ,seward 7#jj7 ,b4 p4 #bjd4 #afca ,dunker 7#df7 ,a4 p4 #ad1 ,pl4 vi4 figs4 #a1 #b4 #afcb ,seward 7#ie7 ,a4 p4 #ia2 see also ,schenk 7#ga7 ,pl4 xxxiv4 #afcc ,sternberg 7#be7 ,a4 p4 xxxii4 #afcd ,brongniart 7#bh7 ,a4 p4 #ic4 ,specimens named by ,brongniart ,cycadites ,nilssoniana are probably fragments of ,dicotyledonous leaves ,nathorst 7#ha7 p4 #hc4 #afce ,holden1 ,r4 7#ad74 #afcf ,nathorst 7#jg74 #afcg ,halle 7#ae74 #afch ,pls4 xii41 xiii4 #afci ,thomas and ,bancroft 7#ac74 #afdj ,heer 7#hb7 ,b4 ,pl4 v4 #afda ,ibid4 7#gh7 ii4 ,pl4 iv4 fig4 #a2 ,nathorst 7#ig7 p4 #chg4 #afdb ,heer 7#gg7 ii4 ,pls4 viii41 xxiii41 xxv4 #afdc ,oldham and ,morris 7#fc7 ,b4 ,pls4 vii41 viii42 ,feistmantel 7#gg7 ,pl4 xlviii4 fig4 #a2 the drawing is very inaccurate4 #afdd ,oldham and ,morris 7#fc7 ,b4 ,pl4 ix4 #afde ,feistmantel 7#gi7 ,pl4 vii4 fig4 #aj2 ,nathorst 7#ji7 p4 #e1 note #b4 #afdf ,goeppert 7#ff74 #afdg ,zeiller 7#jb7 ,b4 ,pl4 vii4 fig4 #d4 #afdh ,nathorst 7#jg7 ,pls4 i4-iii4 #afdi ,seward 7#ie7 ,a4 p #bi1 ,pl4 ii4 fig4 #g2 ,pl4 vi4 fig4 #e2 ,pl4 viii4 fig4 #b4 #afej ,saporta 7#id7 ,b4 p4 #aga1 ,pl4 xxxii4 #afea ,holden1 ,r4 7#ad74 #afeb ,halle 7#ee71 p4 #ejb4 #afec ,schenk 7#ga7 ,b4 ,pl4 xxxii4 fig4 #a4 #afed ,seward 7#ie7 ,a4 pp4 #b-g4 #afee ,halle 7#ae71 ,pl4 xii4 fig4 #ab4 #afef ,zeiller 7#jc7 ,b4 p4 #aee1 ,pl4 xli4 #afeg ,brauns 7#ff7 p4 #ef1 ,pl4 xiv4 fig4 #g2 ,schenk 7#fg7 ,a4 ,pl4 xxxv4 fig4 #aa2 ,seward 7#jd7 ,b4 p4 #cg1 ,pl4 iv4 fig4 #d2 ,pl4 ii4 fig4 #a4 #afeh ,lignier 7#ac7 p4 #ij1 ,pl4 ix4 figs4 #ah1 #ai4 #afei ,brongniart 7#be74 #affj ,nathorst 7#ji74 #affa ,pages #ac1 #af4 #affb ,nathorst 7#ji72 ,thomas and ,bancroft 7#ac74 #affc ,stopes 7#aj74 #affd ,schenk 7#fg7 ,a4 ,pl4 xxix4 figs4 #a1 #b4 #affe ,see vol4 iv4 #afff ,nathorst 7#hf7 ,pl4 xviii4 fig4 #e4 #affg ,ibid4 7#ji7 p4 #bh4 #affh ,thomas 7#ac7 p4 #bda2 ,thomas and ,bancroft 7#ac7 p4 #aic4 #affi ,miquel 7#db7 p4 #fa4 #afgj ,schenk 7#fg7 ,a4 p4 #abg1 ,pls4 xxix41 xxx42 ,nathorst 7#ji7 p4 #aj1 ,pl4 v4 figs4 #i-ac1 etc4 #afga ,for other references see ,nathorst 7#ji7 p4 #aj4 #afgb ,brongniart 7#be7 p4 #bah4 #afgc ,nathorst 7#ji7 p4 #ab1 ,pl4 i4 figs4 #b-ce1 etc4 #afgd ,oldham and ,morris 7#fc7 ,pls4 vii41 viii4 #afge ,feistmantel 7#gg7 p4 #abd4 #afgf ,schenk 7#fg7 ,a4 ,pl4 xxix4 fig4 #aj4 #afgg ,stopes 7#aj74 #afgh ,nathorst 7#hf7 p4 #gb4 #afgi ,ibid4 7#jb7 p4 #ah1 ,pl4 i4 #afhj ,ibid4 7#ji7 p4 #ba1 ,pls4 vi41 vii4 #afha ,phillips 7#bi7 ,a4 p4 #adh1 ,pl4 vii4 fig4 #bj4 ,see ,seward 7#jj7 ,b1 p4 #bbc1 ,pl4 iv4 fig4 #e2 text figs4 #ci1 #dj4 #afhb ,thomas and ,bancroft 7#ac7 p4 #aia4 #afhc ,a specimen in the ,natural ,history ,museum1 ,paris1 labelled ,n4 ,williamsonis is probably that mentioned by ,brongniart4 #afhd ,oldham and ,morris 7#fc7 ,b4 ,pls4 x4-xiii42 ,feistmantel 7#gg7 ,pl4 xlvii4 #afhe ,heer 7#gh7 ii4 ,pls4 xxiii41 xxiv42 ,seward 7#ab7 p4 #bg1 ,pl4 ii4 #afhf ,nathorst 7#ig7 p4 #ac4 #afhg ,yokoyama 7#hi7 ,b4 ,pls4 v41 vii41 xii41 xiii42 ,ward 7#je7 ,b4 ,pl4 xvii4 #afhh ,heer 7#gh7 ii4 p4 #ah1 ,pl4 iv4 figs4 #e-i4 #afhi ,seward 7#jj7 ,b4 p4 #bcj1 fig4 #da4 #afij ,heer 7#hb7 ,b4 ,pl4 vi4 #afia ,for figures and references1 see ,seward 7#aa7 p4 #fie2 ,thomas 7#aa7 p4 #hf4 #afib ,halle 7#ac7 p4 #dg1 ,pls4 v41 vi4 #afic ,fontaine 7#hi7 ,b4 ,pls4 xxx4-xxxv4 #afid ,berry 7#aa7 p4 #cfb1 ,pls4 lvii41 lviii4 #afie ,seward 7#jj7 ,b4 p4 #bbd4 #afif ,nathorst 7#ig7 ,pl4 i4 fig4 #ah4 #afig ,seward 7#ab7 p4 #cj4 #afih ,yokoyama 7#hi7 ,b42 ,nathorst 7#ij7 ,a4 #afii ,stopes 7#aj74 #agjj ,salfield 7#ji7 ,b4 ,pl4 iii4 figs4 #e-g4 #agja ,for references1 see ,seward 7#ab7 p4 #ca4 #agjb ,phillips 7#bi7 ,a4 p4 #adh1 ,pl4 vii4 fig4 #ai4 #agjc ,leckenby 7#fd7 ,a4 p4 #gg2 ,seward 7#jj7 ,b4 p4 #bbg1 ,pl4 iv4 figs4 #a-d4 #agjd ,seward 7#jj7 ,b4 p4 #bbg4 #agje ,krasser 7#ji7 p4 #abj4 #agjf ,seward 7#aa7 p4 #fig4 #agjg ,oldham and ,morris 7#fc7 ,b4 p4 #bc1 ,pls4 x4-xiii42 ,feistmantel 7#gg7 ,pl4 xlvii4 #agjh ,oldham and ,morris 7#fc7 ,b4 ,pl4 xv4 fig4 #a4 #agji ,dunker 7#df7 ,a4 p4 #ae1 ,pl4 i4 fig4 #g1 etc42 ,seward 7#ie7 ,a4 p4 #ec4 #agaj ,schenk 7#ga7 ,b42 ,nathorst 7#ij7 ,a42 ,yokoyama 7#id72 ,fontaine in ,ward 7#je7 ,b42 ,yabe 7#ac74 #agaa ,lindley and ,hutton 7#cd7 ,a4 ,pl4 ciii42 ,phillips 7#bi7 ,a4 ,pl4 vii4 fig4 #ba4 #agab ,zeiller 7#jj7 ,b4 p4 #aae2 ,krasser 7#ji7 p4 #aac4 #agac ,ettingshausen 7#ea74 #agad ,schenk 7#fh74 #agae ,raciborski 7#id7 ,a4 ,pls4 xvii4-xix4 #agaf ,staub 7#if74 #agag ,nathorst 7#hf7 p4 #dc4 #agah ,seward 7#jj7 p4 #ba2 7#jj7 ,b4 p4 #bcb1 figs4 #db1 #dc4 #agai ,raciborski 7#id7 ,a4 ,pl4 xvi4 #agbj ,fontaine 7#hi7 ,b4 p4 #agd1 ,pls4 lxx4-lxxii4 #agba ,krasser 7#ji7 p4 #aac4 #agbb ,nathorst 7#hf7 p4 #hi1 ,pls4 vii41 viii41 xi41 xix4 #agbc ,raciborski 7#ib7 ,pl4 ii4 fig4 #b4 #agbd ,staub 7#if7 #agbe ,ettingshausen 7#ea7 ,pls4 xi41 xii4 #agbf ,schenk 7#fh74 #agbg ,raciborski 7#ib7 ,pl4 ii4 fig4 #b4 #agbh ,ibid4 7#id7 ,a4 ,pl4 xviii4 fig4 #b4 #agbi ,yokoyama 7#jf7 ,b4 ,pl4 ix4 #agcj ,phillips 7#bi7 ,a4 p4 #adh1 ,pl4 vii4 fig4 #ba4 #agca ,lindley and ,hutton 7#cd7 ,a4 ,pl4 ciii4 #agcb ,ward 7#je7 ,b4 p4 #aac4 #agcc ,seward 7#jj7 ,b4 p4 #bce1 ,pl4 viii4 fig4 #b2 ,zigno 7#ef7 ,a4 ,pl4 xxiv4 #agcd ,fontaine in ,ward 7#je7 ,b4 ,pls4 xxvii4-xxviii4 #agce ,seward 7#ab7 ,pl4 iii4 fig4 #dc4 #agcf ,seward 7#jd7 ,b4 p4 #aae4 #agcg ,ibid4 7#jj7 p4 #ba4 #agch ,seward 7#aa7 p4 #fia4 #agci ,ibid4 p4 #gib1 ,pls4 iv41 vii41 viii41 x4 #agdj ,miller 7#eg7 ,b4 figs4 #acc1 #ace4 #agda ,richards 7#hd7 p4 #aag4 #agdb ,seward 7#ie7 ,a4 p4 #hi1 fig4 #e4 #agdc ,tate 7#fg7 ,pl4 v4 fig4 #c2 ,seward 7#jc7 ,b4 ,pl4 v4 fig4 #c4 #agdd ,fontaine 7#hc7 ,b4 ,pls4 xxxix4-xlii4 #agde ,fontaine in ,ward 7#je7 ,b4 ,pl4 xxiii4 #agdf ,seward 7#aa7 ,pls4 iv41 vii4 #agdg ,halle 7#ac7 p4 #ea1 ,pl4 vi4 fig4 #h4 #agdh ,berry 7#aa7 p4 #cdi4 #agdi ,oldham and ,morris 7#fc7 ,pl4 xv4 fig4 #d4 #agej ,ibid4 ,pl4 xv4 fig4 #a42 ,feistmantel 7#gg7 ,pl4 xliii4 fig4 #a4 #agea ,thomas 7#ac7 p4 #bdb1 ,pls4 xxiv41 xxvi4 #ageb ,ibid4 ,pl4 xxvi4 #agec ,feistmantel 7#hf7 ,pl4 ii4 ,a4 figs4 #d-h4 #aged ,brongniart 7#di7 ,a4 p4 #fa4 #agee ,zigno 7#he7 p4 #aje4 #agef ,seward 7#jj7 ,b4 p4 #bae4 #ageg ,renault 7#if7 ,a4 p4 #cbg2 7#ic7 ,a4 ,pl4 lxxxi4 fig4 #a4 #ageh ,seward 7#jd7 ,b4 p4 #aai1 ,pl4 xi4 fig4 #d1 text-fig4 #ab4 #agei ,buckman 7#de7 ,pl4 i4 fig4 #b4 #agfj ,zigno 7#he7 ,pls4 xxxix41 xl4 #agfa ,newberry 7#hh7 ,pl4 viii4 fig4 #ad4 #agfb ,see vol4 iv4 #agfc ,bodenbender 7#jb7 p4 #dj of the reprint4 #agfd ,zeiller 7#id7 ,b4 p4 #agd1 ,pls4 viii41 ix4 #agfe ,renault and ,zeiller 7#hh7 ,a4 p4 #fad1 ,pl4 lxvii4 fig4 #h4 #agff ,zalessky 7#je7 p4 #dja1 fig4 #ac4 #agfg ,potoni 7#ic7 ,a4 p4 #baj1 ,pl4 xxix4 fig4 #e4 #agfh ,zalessky 7#je7 p4 #djc1 figs4 #ad1 #ae4 #agfi ,bassler 7#af74 #aggj ,saporta 7#ge7 ,a4 p4 #aic1 ,pl4 #aad1 fig4 #c2 ,pl4 #aag1 fig4 #a4 #agga ,fliche and ,bleicher 7#hb7 p4 #ba1 fig4 #d4 #aggb ,stopes 7#ae7 p4 #ec4 ,,cambridge3 ,,printed ,,by ,j4 ,b4 ,,peace1 ,m4,a41 ,,at ,,the ,,university ,,press4 ,transcriber's ,notes3 ,text enclosed by underscores is in italics 7italics74 ,text enclosed by pluses is in small caps 7small caps74 ,text enclosed by asterisks is in blackletter font 799blackletter9974 ,blank pages have been removed4 ,obvious typographical errors have been silently corrected4 ,an ,,erratum appears to have been pasted onto page #fjb of the bibliography1 this was moved to follow the bibliography4